# Inside the MS362



## blsnelling (Nov 8, 2009)

I've got a MS362 here for mods and though I'd share my findings. This thing is one strange bird. There's very little familiar about it at all. Everything's new. It couldn't be further from a 361. I've not worked on a 441, so no comparison there.

Squish was .027" with the gasket, and .012" without it. Compression was only 130. The saw is not broke in yet, but I'm still suprised at that low of compression. The piston has two 1.2mm rings, with both end pins very close to the center of the skirt.

I'll just kind of take you through the disassembly here.










































More to come.


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## blsnelling (Nov 8, 2009)




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## Jacob J. (Nov 8, 2009)

Let us know if you would whether it has the 11mm or 12mm wrist pin...


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## blsnelling (Nov 8, 2009)

What's up with this? Perhaps my guage has gone bad, lol.
















The carb box comes off with the removal of two screws.















Can you say Air Injection?


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## blsnelling (Nov 8, 2009)




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## blsnelling (Nov 8, 2009)

Can you say RICH!


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## blsnelling (Nov 8, 2009)

More Air Injection.


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## blsnelling (Nov 8, 2009)




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## blsnelling (Nov 8, 2009)

I forgot to measure port timing before pulling the jug. So the following is with .012" squish and no gasket.

Exhaust 103°
Intake 73°
Transfers 131°

That's it for now.


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## blsnelling (Nov 8, 2009)

Jacob J. said:


> Let us know if you would whether it has the 11mm or 12mm wrist pin...



12mm.


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## Metals406 (Nov 8, 2009)

Them guts on that saw look totally weird compared to the other saws. . . I'm looking forward to your mod and writeup on this animal.


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## blsnelling (Nov 8, 2009)

Metals406 said:


> Them guts on that saw look totally weird compared to the other saws. . . I'm looking forward to your mod and writeup on this animal.



Strato saws are weird for sure. I wonder how similiar this is to the 441? I found the transfers coming from the base of the cylinder rather interesting. All four transfers have their own individual channels. And check out that transfer port timing! Tons of blowdown on this thing.


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## Metals406 (Nov 8, 2009)

blsnelling said:


> Strato saws are weird for sure. I wonder how similiar this is to the 441? I found the transfers coming from the base of the cylinder rather interesting. All four transfers have their own individual channels. And check out that transfer port timing! Tons of blowdown on this thing.



I can see that being a big advantage to modding it. . . It seems that's what most guys always want a little more of on a built saw.


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## blsnelling (Nov 8, 2009)

Metals406 said:


> I can see that being a big advantage to modding it. . . It seems that's what most guys always want a little more of on a built saw.



Particularly true on piped saws. I'll likely be raising these transfers a little.


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## Metals406 (Nov 8, 2009)

blsnelling said:


> Particularly true on piped saws. I'll likely be raising these transfers a little.



Exactly. . . Time and area are your friend.


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## splitpost (Nov 8, 2009)

:jawdrop:Thats one very different looking jigger,can i assume thats a twin throttle type set up, to increase response across the rev range?


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## stihlavarna (Nov 8, 2009)

I've never seen stops on the ends of rings before


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## Jacob J. (Nov 8, 2009)

Brad- great pictures as always. Yes, this one looks like the little brother to the 441. The port arrangement is the same. I believe those upper cut-outs on the sides of the piston help with transfer timing, although I have not been inside a 441 enough yet to have mapped it out.


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## WoodChuck'r (Nov 8, 2009)

Stratos are odd, very odd.


Great pics though.


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## Andyshine77 (Nov 8, 2009)

blsnelling said:


> Can you say RICH!



The P&C look similar to the pics of the 441 I've seen. Not to start an oil thread, but what kind of oil was ran in this saw? the combustion chamber and piston crown look horrible.


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## Andyshine77 (Nov 8, 2009)

It's 2:00 AM and I just went out to the garage and checked the compression on my 362. lol Anyway it's 150 dead.


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## tdi-rick (Nov 8, 2009)

stihlavarna said:


> I've never seen stops on the ends of rings before



Do you mean the ring pins on the piston ??

Most/all two strokes have to have them, otherwise the the rings would rotate and the ends would snag in a port.


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## tdi-rick (Nov 8, 2009)

splitpost said:


> :jawdrop:Thats one very different looking jigger,can i assume thats a twin throttle type set up, to increase response across the rev range?



Naa,the second throttle is to introduce the straight air (no mix) that is introduced in front of the charge in the transfers to help purge the exhaust and stop fresh charge flowing clean out.


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## BlueRidgeMark (Nov 8, 2009)

Andyshine77 said:


> It's 2:00 AM and I just went out to the garage and checked the compression on my 362.




You are a sick man, Andy.


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## rms61moparman (Nov 8, 2009)

Is it just me or is there an excessive amount of carbon buildup on top of the piston for a practically new saw???

I would think this saw, running at those settings over a long period of time would have been a candidate for serious carbon scoring.

and 

Do you reckon those port castings were left that rough on purpose attempting to improve atomization???


Mike


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## Terry Syd (Nov 8, 2009)

*Stratos*

Brad, I've tried three times to load your pictures, but my useless computer system won't let me look at all the pictures. I note that someone mentioned a cutaway in the top of the piston. On my 450 Husky that cutaway also has a hole through the piston. I kept wondering about it and I think I know what that cutaway and hole is for on the 450.

The temperature gradients over the piston skirt are likely fairly radical with the strato function blowing across the sides of the skirt. The piston doesn't have to conduct the heat from the skirt through the cylinder and to the cooling air outside the cylinder - it's being cooled directly.

The cutaway on mine is open to the strato port for a short period and allows fresh air to flow to the front of the piston and inside to the hot area at the front and top of the piston. I believe this was done to give the piston a more uniform expansion (it also allows a cooler running piston).

You may want to compute the strato duration. On the 450 the strato port is open before the intake port. The intake has a duration of 144 and the strato port is something like 150. (I forget what it was, but it is longer). That is an interesting twist to my strato in that at idle the intake timing is reduced, but as you open the throttle and the revs build, you get to a point where the throttle starts opening the strato butterfly and the total intake port timing gains duration. It's kind of like a variable timing camshaft (there is also the further analogy to the secondaries on a carburetor with the strato butterfly opening).

Something else to consider, since you dropped the jug, you have also extended the strato timing, something you may want to factor in if you are thinking about extending the intake timing.

If you could post some further pictures of the piston and the transfer ports I'd appreciate it. I'm definitely looking forward to what you come up with on this strato mod.

Edit: the pictures finally loaded. It looks like the Stihl design is very different to the design of the Husky 450. Conceptually it is the same, but entirely different approaches to implement it.


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## demographic (Nov 8, 2009)

tdi-rick said:


> Do you mean the ring pins on the piston ??
> 
> Most/all two strokes have to have them, otherwise the the rings would rotate and the ends would snag in a port.




I don't know saws but every two stroke engine I have seen apart had ring stops to stop them from rotating and snagging like you said.

Four strokes don't have lots of holes in the bore so that's not an issue.

Great thread, its interesting to see the way those stratos are ported.


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## alderman (Nov 8, 2009)

Brad:

Nice tutorial.

I'm impressed and I don't even know what I'm looking at or what the he** you're talking about most of the time.

Did you get to run that saw before you started the teardown?


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## gink595 (Nov 8, 2009)

blsnelling said:


>



What is the little hole at the bottomof the cylinder for...Impulse line


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## blsnelling (Nov 8, 2009)

splitpost said:


> can i assume thats a twin throttle type set up, to increase response across the rev range?


No. It's part of the strato design. It makes the saw cleaner burning and more efficient.



stihlavarna said:


> I've never seen stops on the ends of rings before


Most all saws have them.



Andyshine77 said:


> It's 2:00 AM and I just went out to the garage and checked the compression on my 362. lol Anyway it's 150 dead.


I think the Schrader valve was loose in my hose. Compression was down about 25 PSI on my 681 too, and there's nothing wrong with it.



rms61moparman said:


> Is it just me or is there an excessive amount of carbon buildup on top of the piston for a practically new saw???





Andyshine77 said:


> Not to start an oil thread, but what kind of oil was ran in this saw? the combustion chamber and piston crown look horrible.


I think it's very excessive. I'm assuming the saw was running WAY rich. I have no idea what oil was used. It was green though. I'm assuming it was Stihl oil.



gink595 said:


> What is the little hole at the bottom of the cylinder for...Impulse line


Yes, it's the impulse passage. No hose to go bad on this model.


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## parrisw (Nov 8, 2009)

opcorn:


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## Erick (Nov 8, 2009)

So Brad, what's the approach gonna be to this build??? Gotta plan yet?


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## mtngun (Nov 8, 2009)

Thank you much for the pics, Brad.


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## blsnelling (Nov 8, 2009)

Erick said:


> So Brad, what's the approach gonna be to this build??? Gotta plan yet?



I sat staring at this thing until after 1AM this morning, lol.


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## Terry Syd (Nov 8, 2009)

*Zen*

"I sat staring at this thing until after 1AM this morning, lol." 

I know what you're talking about, I went through a number of permutations of how my strato worked. Each time I picked up the jug I found another "now why did they do this?"

If we could get some SAE papers on the designs it might save a lot of Zen time.


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## stihlboy (Nov 8, 2009)

this will be the first 362 ported as far as we all know!!! don't screw it up! lol just kidding brad you do good work...........on a side note wanna port a 5105?


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## gink595 (Nov 8, 2009)

blsnelling said:


> I sat staring at this thing until after 1AM this morning, lol.



So when you start a port job is there a precedure you normally do... Measurements, timing numbers... What is the process you have when you start a woods port? What makes this one that much differnt? I do understand it is a different design than what you have done but is the idea the same?


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## huskystihl (Nov 8, 2009)

blsnelling said:


> No. It's part of the strato design. It makes the saw cleaner burning and more efficient.
> 
> 
> think it's very excessive. I'm assuming the saw was running WAY rich. I have no idea what oil was used. It was green though. I'm assuming it was Stihl oil.
> ...


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## walexa07 (Nov 8, 2009)

Brad, regarding low compression numbers........is it possible that the decompression valve is leaky? I had that same trouble on my 361 and bought the stihl plug for it and the compression came way up.

Waylan


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## parrisw (Nov 8, 2009)

gink595 said:


> So when you start a port job is there a precedure you normally do... Measurements, timing numbers... What is the process you have when you start a woods port? What makes this one that much differnt? I do understand it is a different design than what you have done but is the idea the same?



Ya just start grinding until it looks good, then call it done!!


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## blsnelling (Nov 8, 2009)

gink595 said:


> So when you start a port job is there a precedure you normally do... Measurements, timing numbers... What is the process you have when you start a woods port? What makes this one that much differnt? I do understand it is a different design than what you have done but is the idea the same?


I take the measurements I posted earlier. I then study the P&C and decide where I want to go with it. I'm also noticing skirt width limitations and ring pin locations and how they affect what I can/cannot do.



huskystihl said:


> Thats the way my 441 looked after running hp ultra. All carboned to beat heck. I switched to a synthetic without all the additives and it cleared right up, lost the shelf life of the fuel but it never sits more than a week anyways.


I found out this was orange bottle Stihl. The saw has only seen about 3 tanks of fuel.



walexa07 said:


> Brad, regarding low compression numbers........is it possible that the decompression valve is leaky? I had that same trouble on my 361 and bought the stihl plug for it and the compression came way up.


I really think it was my compression guage.


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## Rounder (Nov 8, 2009)

Would not touch it with a 10 ft. pole. 

I had to tell the guys on the crew to stop buying 441's- To much trouble to work on. - I see more of the same - Sam


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## blsnelling (Nov 8, 2009)

mtsamloggit said:


> Would not touch it with a 10 ft. poll. -Sam



How about a 1/4" or 1/8" burr?


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## Rounder (Nov 8, 2009)

blsnelling said:


> How about a 1/4" or 1/8" burr?



How's about 1/2"!- Ha- Seriously, good luck, and I will be very curious to see what transpires. At the end of the day all of us ding dongs who run saws for a living are going to have to adjust. As I've seen you write before, stock saws suck, so we're going to have to figure these things out. - Sam


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## parrisw (Nov 8, 2009)

mtsamloggit said:


> How's about 1/2"!- Ha- Seriously, good luck, and I will be very curious to see what transpires. At the end of the day all of us ding dongs who run saws for a living are going to have to adjust. As I've seen you write before, stock saws suck, so we're going to have to figure these things out. - Sam



Its already been proven that these things can be ported with very good gains. Slinger did 441 that was very impressive.


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## Wild Knight (Nov 8, 2009)

Do you map the cylinder to make measurements on the ports and transfers? Will you post a copy of it and the measurements?


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## Wild Knight (Nov 8, 2009)

Andyshine77 said:


> It's 2:00 AM and I just went out to the garage and checked the compression on my 362. lol Anyway it's 150 dead.



LOL! I assumed this was yours!


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## Philbert (Nov 8, 2009)

*Brad, Thank you very much for sharing this with us.*

Philbert


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## stihlboy (Nov 8, 2009)

wow.


Currently Active Users Viewing This Thread: 21 (20 members and 1 guests) 
stihlboy, Philbert, xxl, forestryworks, LarryTheCableGuy, bubber, gonecountry, Wild Knight+, Grfi, BloodOnTheIce+, palogger, SpaayDawg, dmh, les-or-more, nassin2, Jacob J.+, cooper426 
....


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## Rounder (Nov 8, 2009)

parrisw said:


> Its already been proven that these things can be ported with very good gains. Slinger did 441 that was very impressive.



Is there any archived info on that? Had a buddy who did a 441 that sounded good, but actual gains weren't that great (not sure exactly what he did). The cable throttle linkage was the big "no no" for me. Anybody know if the 362 runs the same setup? -Sam


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## blsnelling (Nov 8, 2009)

Wild Knight said:


> Do you map the cylinder to make measurements on the ports and transfers? Will you post a copy of it and the measurements?


I do not use port maps.



Wild Knight said:


> LOL! I assumed this was yours!


No, this is not Andy's saw. The owner of the saw is aware of this thread and can respond as they so choose.



mtsamloggit said:


> Is there any archived info on that? Had a buddy who did a 441 that sounded good, but actual gains weren't that great (not sure exactly what he did). The cable throttle linkage was the big "no no" for me. Anybody know if the 362 runs the same setup? -Sam


There are no cables on the 362.


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## parrisw (Nov 8, 2009)

mtsamloggit said:


> Is there any archived info on that? Had a buddy who did a 441 that sounded good, but actual gains weren't that great (not sure exactly what he did). The cable throttle linkage was the big "no no" for me. Anybody know if the 362 runs the same setup? -Sam



I'll see if I can find it.


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## parrisw (Nov 8, 2009)

mtsamloggit said:


> Is there any archived info on that? Had a buddy who did a 441 that sounded good, but actual gains weren't that great (not sure exactly what he did). The cable throttle linkage was the big "no no" for me. Anybody know if the 362 runs the same setup? -Sam



Here it is.

http://www.arboristsite.com/showthread.php?t=100424


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## Erick (Nov 9, 2009)

Be sure and take lots of pics on this one Brad.... I think there may be some interest. 







No pressure.


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## blsnelling (Nov 9, 2009)

Erick said:


> Be sure and take lots of pics on this one Brad.... I think there may be some interest.
> 
> 
> 
> ...



Ya think Just a little maybe Yes, I know, I'm sticking my neck out again on this one. But that's ok. I knew everyone would be interested in checking out the next generation of saw.


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## bitzer (Nov 9, 2009)

Very cool! The Husky 455 strato is very similar in set up to this. The ring end is right down the middle and allows for very little widening of the intake so I lowered it a little. Piston looks nearly identical. The transfers are different on mine, but open at the base like this one. Its good to see four transfers on the 362 instead of the two I have on mine (which is not a pro saw tho). I acutally raised the bottom of the transfers some where the webbing meets the base, but its a clamshell. I also raised and pointed the transfers up and back to get as much fresh charge in the chamber before the strato ports open. Widened the exhust and put a second port on the muff of course. Its a whole new animal since then. Its great to see the step by step with pics! Once again, Thanks Brad!


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## bitzer (Nov 9, 2009)

Brad,

Its hard to tell from the pics, but is the carb fully adjustable? It looks like there is a spot for the screws. Before I started work on my 455 I undid the linkage of the strato port to see what would happen when running WOT. The factory max rich setting on the H screw is 2.5 turns out and when the linkage was undone It would only get up to about 9K all the way to 1/2 a turn out. I started it at 2.5 and turned it in a little at a time checking it until I got to a 1/2 turn. It was still WAY rich then so I realized it needs the extra strato air in the combustion. The tranfers on the 455 are a lot longer though and there are only 2. It will be interesting to see what you come up with!


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## forestryworks (Nov 9, 2009)

pretty fancy saw


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## stipes (Nov 9, 2009)

*That saw and layout is weird....*

Good luck on it Brad!! Wow,,where do you start??? I was amazed with the carbon buildup with only a few tanks..and I thought I ran my stuff rich...With a epa type saw,,that suprised me!!!


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## volks-man (Nov 9, 2009)

bah!
second butterfly be damned!!!

fab an adapter that fits on the carb box, fit a bigger carb (066?) to the adapter, and let both strato and regular intake pull air/fuel from the carb. port the snot out of the exhaust.
then set the squish tight and have a blast!

why not?


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## blsnelling (Nov 9, 2009)

The saw is back together and running. It's holding 11,500 in the wood! I'm hoping to get wih Andy and Nik tomorrow night to run it against Andy's stock 362 and Niks ported 361. I think we've got a winner here

Some have thought this saw to be rev limited. This one is not. Interestingly enough, this saw does not turn as many RPMs at WOT as a conventionally ported saw, but it's really holding them in the wood where it counts. Leaned out to straight 2-stroking, it'll turn 14,400. 14,000 is likely the max you'd want to run it. I've got it set at 13,600 right now and it's quite rich.


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## BloodOnTheIce (Nov 9, 2009)

Brad glad it came together well. I can't wait to run it. 
The running rich, has me baffled especially since I have run only a couple tanks through it, and have never seen that sort of build up on such a new saw.
But as stated in the thread I may need to be careful which oil I run, and may have to try some different brands and see which works best. 
I posted it before but here it was stock. That bar was not the new one that came w/ the saw. 
My rakers were set too low and I'm leaning on it pretty good w/ most of my 260 pounds. 
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/yAwlNDEccSg&hl=en&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/yAwlNDEccSg&hl=en&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>


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## blsnelling (Nov 9, 2009)

BloodOnTheIce said:


> Brad glad it came together well.
> The running rich, has me baffled especially since I have run only a couple tanks through it, and have never seen that sort of build up on such a new saw.
> But as stated in the thread I may need to be careful which oil I run, and may have to try some different brands and see which works best.



Perhaps Stihl Ultra will keep it clean. I'd go full synthetic, whatever you go with.


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## Andyshine77 (Nov 9, 2009)

The non synthetic Stihl oils run really dirty, Echo's oil is a much better choice if you want to run a non syn, but I'd run a good full syn.

Here's my well used ported 7900 piston, I've been running Klotz R50 for about two years now.


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## Erick (Nov 9, 2009)

Ummmmm.......



Erick said:


> Be sure and take lots of pics on this one Brad.... I think there may be some interest.



:Eye: :Eye:
:dunno:


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## parrisw (Nov 9, 2009)

Erick said:


> Ummmmm.......
> 
> 
> 
> ...



:agree2::agree2:

video as well.


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## Erick (Nov 10, 2009)




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## parrisw (Nov 10, 2009)

Andyshine77 said:


> The non synthetic Stihl oils run really dirty,



I'll second that, I repair a tree service's saws, and they run stihl dino, and ya, their saws are pretty dirty, inside and out.


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## Freehand (Nov 10, 2009)

:camera:opcorn:


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## shwinecat (Nov 10, 2009)

Thanks as usual Brad for the great thread and the photos. I have been on the fence with these new saws and had no idea Tslinger had done a 441 until this forum.

If this build goes well there are going to be a lot of smiley faces going around. If it goes bad AS better have some free counseling on this sight. I can't wait to get the results so please hurry. So far it's been like the teenage boy reading Penthouse Forum with the last page missing.

Thanks again Brad and I know you take some heckling from other members on this sight but you have really taken this forum to a new level with the photos and openness of your talents.


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## blsnelling (Nov 10, 2009)

I'm not sure I should show pictures of my porting before I have confirmation that it actually worked, lol. I will be making a video this evening comparing this saw to a stock 362 and ported 361, running the same B&C on all saws. It'll be late tonight before I get it posted though.


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## Philbert (Nov 10, 2009)

BloodOnTheIce said:


> <object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/yAwlNDEccSg&hl=en&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/yAwlNDEccSg&hl=en&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>



BOTI,

(_nice look - Converse tennis shoes with chaps! - Kevlar laces?_)

Philbert


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## Curlycherry1 (Nov 10, 2009)

Great thread and I see the bleachers are pretty full with spectators. I see popcorn is available but someone needs to be selling wings and beer!

Thanks for the info on the rebuild and looking forwared to the final showdown video.

Somewhat new to the AS forum and someone is probably going to thump me for asking but what is the best oil to run in a Stihl. I have blown up saws in the past by using bad oil and I am about to get a new MS660 and it has been a long while since I paid attention to oil, and it seems to have changed a lot! Is there a thread about oil somewhere that I am missing? Is this as bad a topic to open up as which saw is better, Stihl/Husky/Dolmar?


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## Freehand (Nov 10, 2009)

:arg::notrolls2::welcome::dunno:


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## parrisw (Nov 10, 2009)

Curlycherry1 said:


> Great thread and I see the bleachers are pretty full with spectators. I see popcorn is available but someone needs to be selling wings and beer!
> 
> Thanks for the info on the rebuild and looking forwared to the final showdown video.
> 
> Somewhat new to the AS forum and someone is probably going to thump me for asking but what is the best oil to run in a Stihl. I have blown up saws in the past by using bad oil and I am about to get a new MS660 and it has been a long while since I paid attention to oil, and it seems to have changed a lot! Is there a thread about oil somewhere that I am missing? Is this as bad a topic to open up as which saw is better, Stihl/Husky/Dolmar?



I hear Stihl Ultra is good. I use Amsoil Sabre professional for years now, its great stuff.


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## stinkbait (Nov 10, 2009)

parrisw said:


> I hear Stihl Ultra is good. I use Amsoil Sabre professional for years now, its great stuff.



+1 

Amsoil exhaust smells funny though.


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## parrisw (Nov 10, 2009)

stinkbait said:


> +1
> 
> Amsoil exhaust smells funny though.



Ya?? I'm used to it by now I guess. Funny you mention that, every time I go out with my buddy's tree service, he says, your exhaust smells funny. LOL


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## TJ-Bill (Nov 10, 2009)

opcorn:


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## stinkbait (Nov 10, 2009)

parrisw said:


> Ya?? I'm used to it by now I guess. Funny you mention that, every time I go out with my buddy's tree service, he says, your exhaust smells funny. LOL



I kind of like it.


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## parrisw (Nov 10, 2009)

stinkbait said:


> I kind of like it.



Ya, I do to. Reminds me of racing actually.


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## Jacob J. (Nov 10, 2009)

Andyshine77 said:


> The non synthetic Stihl oils run really dirty, Echo's oil is a much better choice if you want to run a non syn, but I'd run a good full syn.



I'll second that on the Echo dino-based oil. We had two cases left over at the shop from a sales promotion. The company didn't want it so I ran it in the woods on a thinning job. It did very well and burned clean.


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## ShoerFast (Nov 10, 2009)

blsnelling said:


> The saw is back together and running. It's holding 11,500 in the wood! I'm hoping to get wih Andy and Nik tomorrow night to run it against Andy's stock 362 and Niks ported 361. I think we've got a winner here
> 
> Some have thought this saw to be rev limited. This one is not. Interestingly enough, this saw does not turn as many RPMs at WOT as a conventionally ported saw, but it's really holding them in the wood where it counts. Leaned out to straight 2-stroking, it'll turn 14,400. 14,000 is likely the max you'd want to run it. I've got it set at 13,600 right now and it's quite rich.



Brad

Thanks for the thread, it's very interesting!  

For a think...
Is there a chance that the strato-charge gets more involved with the AF-charge more under a load then free-tuning? (as it seems to be on the fat side till it hits wood?) (this might explain why it looked to have been run fat at tare-down (as it needs to be under-load/working to fully use the extra charge?) ? )

That would indicate that the combustion chamber dynamites and programed ignition are counting on the saw being under a load. 




It would be interesting what your work to this saw dose tuning for timed cuts?

I know this is not making much sense, but for a think, what if the ignition timing backed off at anything over 13.5K and give-er h311 at anything under 13.5K ? (counting on a load in the wood for your max-timing and sort of protect the engine out of the wood?) Timed cuts or an advancing timing light will tell you this. 

This would give you your interesting free-tune results? 

If my hunch is right, this is a candidate to be run at a slightly richer oil:fuel ratio, slightly richer air:fuel ratio, as it is getting some of it's combustion air from another source, and under a load, it really goes to town?


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## blsnelling (Nov 10, 2009)

My thinking was kind of the opposite. The new additional transfer bring in fresh are from the top butterfly. This air is not mixed with fuel. How is that different from an air leak? Wouldn't that cause the saw to run lean?


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## ShoerFast (Nov 10, 2009)

blsnelling said:


> My thinking was kind of the opposite. The new additional transfer bring in fresh are from the top butterfly. This air is not mixed with fuel. How is that different from an air leak? Wouldn't that cause the saw to run lean?



Well yes, but the carb needs to be extra rich to give the 12:1 or what ever it needs to be the best 'under-load' setting. 

That extra charge might act (scavenge) differentially under a load then it dose free-turning? 

Combine that with a wild ignition timing curve (chip) and your going to loose a little hair on the first one, I would, I envoy your challenge!


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## kevlar (Nov 10, 2009)

blsnelling said:


> My thinking was kind of the opposite. The new additional transfer bring in fresh are from the top butterfly. This air is not mixed with fuel. How is that different from an air leak? Wouldn't that cause the saw to run lean?



It's my understanding that this puff of air is introduced just before the intake charge is pushed in, pushing out the exhaust while making a wall of air that keeps the @ 25% of raw hydro carbons from going out with the exhaust (epa hates that) so my thinking is maybe the extra fuel being kept in the cylinder is making it rich (like was stated above) until under load.


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## blsnelling (Nov 10, 2009)

I'm understanding what you're saying now. However, the fresh air ports are below the transfers. That would put the fresh air after the charge, correct?


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## kevlar (Nov 10, 2009)

blsnelling said:


> I'm understanding what you're saying now. However, the fresh air ports are below the transfers. That would put the fresh air after the charge, correct?



The ports in the piston hold the puff until the next intake


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## blsnelling (Nov 10, 2009)

kevlar said:


> The ports in the piston hold the puff until the next intake



Ahh, gotcha.


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## blsnelling (Nov 10, 2009)

I wonder if this technology is also somehow keeping max RPMs down at WOT, no load? A ported 361 will turn a lot more RPMs at WOT. This one likes 13,600-14,000, but holds great RPMs in the wood.


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## ShoerFast (Nov 10, 2009)

blsnelling said:


> I wonder if this technology is also somehow keeping max RPMs down at WOT, no load? A ported 361 will turn a lot more RPMs at WOT. This one likes 13,600-14,000, but holds great RPMs in the wood.



Yup! 

What I was thinking! 

Your going to find out what I'm dieing to know is the pure potential of the strato-port or is it all just to clean up the emissions? 

Cool project!


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## blsnelling (Nov 10, 2009)

ShoerFast said:


> Yup!
> 
> What I was thinking!
> 
> ...



I think it's really just more intimidating than it is punishing. It's not what we're used to, so we're scared of it. In sounds like, the only difference is the extra air to push out the exhaust rather than fuel/air mix. So the extra butterfly, pockets in the piston, and extra ports look confusing. Ignore that, and it's the same old ballgame. We'll find out tonight. I'm leaving immediately after work and will be making the comparison video down at Andy's place. You coming up Mike?


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## ShoerFast (Nov 10, 2009)

blsnelling said:


> I think it's really just more intimidating than it is punishing. It's not what we're used to, so we're scared of it. In sounds like, the only difference is the extra air to push out the exhaust rather than fuel/air mix. So the extra butterfly, pockets in the piston, and extra ports look confusing. Ignore that, and it's the same old ballgame. We'll find out tonight. I'm leaving immediately after work and will be making the comparison video down at Andy's place. You coming up Mike?



Back in the day, Honda had a 3rd valve in there Civic engine. It had it's own carb port and everything. 

Took me for a spin to figure it out. 

Mentioning it here as it was just the opposite, that 3rd valve and carb port ran pig-fat rich! It function in life was to fatten up the compression/mix right next to the plug to fire the rest of the mix as it was boarder-line lean. 

They ran like a top with set up right, 50 MPG was easy with 4 people cramped inside them. 

When I seen them was after someone disabled the 3rd port at the first sign of a drive-ability problems,,,, and that's when the problems really started. 

Looking forward to the vid Brad! 

Thanks!


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## blsnelling (Nov 10, 2009)

ShoerFast said:


> Looking forward to the vid Brad!
> 
> Thanks!



I've got myself setup for either great success OR great failure! But I've always been an open book. Why change now? If I was smart, lol, I'd wait until I had known good gains before showing anything. But that's just not my style. Good or bad, you guys get to see inside this baby.


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## Curlycherry1 (Nov 10, 2009)

blsnelling said:


> I've got myself setup for either great success OR great failure! But I've always been an open book. Why change now? If I was smart, lol, I'd wait until I had known good gains before showing anything. But that's just not my style. Good or bad, you guys get to see inside this baby.



We're rooting for ya! Remember what they say, no guts, no glory. opcorn:


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## rms61moparman (Nov 10, 2009)

blsnelling said:


> I'm leaving immediately after work and will be making the comparison video down at Andy's place. You coming up Mike?



By the time I broke out of the salt mine and got up there, it would be over, and time to come back and prepare for the next day of salt mining!!!LOL

But MAN how I wish I could be there for the "trials"!

Mike


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## epicklein22 (Nov 10, 2009)

ShoerFast said:


> Back in the day, Honda had a 3rd valve in there Civic engine. It had it's own carb port and everything.
> 
> Took me for a spin to figure it out.
> 
> ...



Yaya, my dad rebuilt one of those honda engines back in the day. I showed him the pictures of this 362 and that honda was one of the first things he mentioned.


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## woodgrenade (Nov 10, 2009)

<embed id=VideoPlayback src=http://video.google.com/googleplayer.swf?docid=2742473104102029339&hl=en&fs=true style=width:400px;height:326px allowFullScreen=true allowScriptAccess=always type=application/x-shockwave-flash> </embed>

Its the final countdown! I have faith in ya Brad.


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## ShoerFast (Nov 10, 2009)

blsnelling said:


> I've got myself setup for either great success OR great failure! But I've always been an open book. Why change now? If I was smart, lol, I'd wait until I had known good gains before showing anything. But that's just not my style. Good or bad, you guys get to see inside this baby.



Kudos to your style! 

That's pure class! 

After first hand word-of-mouth accounts about your work one could expect nothing less! 

Your work proceeds your post(s) , there is not a higher accomplishment!


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## parrisw (Nov 10, 2009)

Jacob J. said:


> I'll second that on the Echo dino-based oil. We had two cases left over at the shop from a sales promotion. The company didn't want it so I ran it in the woods on a thinning job. It did very well and burned clean.



That's good to hear, the Echo oil around here is a good price, I almost switched to it this year when I couldn't find a local dealer for Amsoil, but I found a guy close by.


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## bitzer (Nov 10, 2009)

blsnelling said:


> I'm understanding what you're saying now. However, the fresh air ports are below the transfers. That would put the fresh air after the charge, correct?



I posted this on page four. 

"Before I started work on my 455 I undid the linkage of the strato port to see what would happen when running WOT. The factory max rich setting on the H screw is 2.5 turns out and when the linkage was undone It would only get up to about 9K all the way to 1/2 a turn out. I started it at 2.5 and turned it in a little at a time checking it until I got to a 1/2 turn. It was still WAY rich then, so I realized it needs the extra strato air in the combustion."

By linkage I mean the butterfly that opens the strato port linkage.

What I'm thinking is that the EPA is after controlling unburnt hydrocarbons emmisions, by the addition of extra air from the strato ports it casues a more efficient burn of the mix.


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## blsnelling (Nov 11, 2009)

As promised, the video is done. As promised, it's late, lol.

I couldn't be more pleased! The 362 really responded to the porting. Based on this round of testing, it was 26% faster than stock in about 12" wood, and 18% faster than stock with the 20" bar buried. 

In the smaller wood, it was neck and neck with the ported 361. In the bigger wood, the 361 takes over and was 9% faster than the ported 362. It just has more torque, plain and simple. 

So really nothing too surprising here. The 362 responded very well to mods, but still not like a non-strato saw. 

But don't look at just the numbers. This ported 362 is a pleasure to run. It's very strong and is very smooth. It'll get better fuel economy as well. Only for the racer is the strato design that big of a deal. 

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/UlJa-G3vGuA&hl=en&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/UlJa-G3vGuA&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>


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## parrisw (Nov 11, 2009)

Looks really good.


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## Freehand (Nov 11, 2009)

Wow that solo was really moving...........opcorn:


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## Andyshine77 (Nov 11, 2009)

blsnelling said:


> But don't look at just the numbers. This ported 362 is a pleasure to run. It's very strong and is very smooth. It'll get better fuel economy as well. Only for the racer is the strato design that big of a deal.



Well said and :agree2:

BTW Both 362's are really new and they will only get stronger.


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## blsnelling (Nov 11, 2009)

Andyshine77 said:


> Well said and :agree2:



Thanks for hosting us tonight, Andy. It's always a pleasure.


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## Andyshine77 (Nov 11, 2009)

No problem, it's always fun to hang out with you guys.


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## dragrcr (Nov 11, 2009)

good work brad, she really holds the rpm in the cut, I am supprised at the low RPM with the port timming like it is. You can tell it really dosnt like to be loaded hard. BTW blood sold me that saw so you can just go ahead and ship it to me.....


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## Metals406 (Nov 11, 2009)

blsnelling said:


> As promised, the video is done. As promised, it's late, lol.
> 
> I couldn't be more pleased! The 362 really responded to the porting. Based on this round of testing, it was 26% faster than stock in about 12" wood, and 18% faster than stock with the 20" bar buried.
> 
> ...



Thanks for the thread and all your hard work Brad!

One thing to consider on this mod. . . It's the first one. The "super-secret recipe" for porting these strato saws probably isn't found yet. There are probably more gains to be had, it's just a matter of time.

Thanks again for posting all this.


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## dingeryote (Nov 11, 2009)

Nice work Brad, and Thanks!

I ain't got a dog in the fight, but the matter of fingering out what makes the new strato horrors tick, is deeply interesting.

Maybe with some fussing on port timing that difference between the 361 and 362 in larger logs can be ironed out.

Stay safe!
Dingeryote


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## Jacob J. (Nov 11, 2009)

Great work Brad- being on the leading edge of knowing the strato-charged engines is a huge asset... though I really like how the Solo 681 came in and took charge.


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## woodgrenade (Nov 11, 2009)

Great vid, and job well done. The saw made some great gains and that is all you could ask for. I hope the vid I posted before served as inspiration! lol.


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## BloodOnTheIce (Nov 11, 2009)

Looks good, I can't wait to run it. And no I didn't sell it and it's not for sale. 
And this saw only has a few tanks of gas through it and should pick up a little more when it's got a few hours on it. I didn't have this saw ported to to beat a 361, I wanted to see what could be done w/ this new technology. Thanks again Brad.


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## Wild Knight (Nov 11, 2009)

Brad: when you do a port job, how do you know how much material you want to remove, and how do you measure how much has been removed?

On this job, how much did you widen the ports or change the transfers?

What was the final compression?

How wide did you go with the muffler mod?

Did you advance the timing?

Will you post pics?


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## wigglesworth (Nov 11, 2009)

Wild Knight said:


> Brad: when you do a port job, how do you know how much material you want to remove, and how do you measure how much has been removed?
> 
> On this job, how much did you widen the ports or change the transfers?
> 
> ...



and Brad, dont forget your mothers maiden name....


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## Fastcast (Nov 11, 2009)

Interesting stuff!....Great work gentlemen!


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## stinkbait (Nov 11, 2009)

Nice work Brad!

Dang that 681 is fast for stock!


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## constantine (Nov 11, 2009)

Thanks for all the hard work and the excellent video. I won't run out to trade my 361 for a 362, but I'm getting a 681 for sure! It will take time and experimentation to figure out the best way to achieve maximum performance from the strato engine. I'm sure that even at peak performance, there will be tradeoffs between strato and conventional designs. The fuel economy is undeniable, even at this early stage, however. Keep up the great work and thanks for sharing it with all of us.


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## blsnelling (Nov 11, 2009)

dragrcr said:


> You can tell it really dosnt like to be loaded hard.


It does prefer a "medium" touch. The 361 can be loaded quite a bit more.



Metals406 said:


> One thing to consider on this mod. . . It's the first one. The "super-secret recipe" for porting these strato saws probably isn't found yet. There are probably more gains to be had, it's just a matter of time.


20%-25% are respectable gains for a woods port on any saw. I really think we're seeing the limitations of the strato design here. I'm sure you could go farther, but it would beyond the realms of a wood port. A popup would likely help a little.



dingeryote said:


> Maybe with some fussing on port timing that difference between the 361 and 362 in larger logs can be ironed out.


See above. 



Jacob J. said:


> ... though I really like how the Solo 681 came in and took charge.


Kind of puts things into perspective doesn't it?



woodgrenade said:


> The saw made some great gains and that is all you could ask for.


I'm very pleased with the results. I was high 5ing Nik as soon as we timed the first cut. I knew we had success.



BloodOnTheIce said:


> Looks good, I can't wait to run it. And no I didn't sell it and it's not for sale.
> And this saw only has a few tanks of gas through it and should pick up a little more when it's got a few hours on it. *I didn't have this saw ported to to beat a 361, I wanted to see what could be done w/ this new technology.* Thanks again Brad.


You're quite welcome. Thanks for the opportunity to be the first to go inside a 362. That was really cool. I know beating the 361 wasn't the ultimate goal, but I also know that's a huge question on everyone's mind. So I had two questions going into this. How does it compare to stock? And, how does it mod compares to the 361? Don't let the fact that the 361 was faster confuse you. The gains to this 362 were everything, and more, than I hoped for. It's just a different saw.


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## bitzer (Nov 11, 2009)

Will you give us the pics man? The video is only the teaser! Im curious as hell to see what you did! Very cool Brad! Thanks for keeping it out there!


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## blsnelling (Nov 11, 2009)

stinkbait said:


> Dang that 681 is fast for stock!



And it's still wearing a little 7-pin rim. I'm out of 8-pins or it would be measurably faster yet


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## blsnelling (Nov 11, 2009)

bitzercreek1 said:


> Will you give us the pics man? The video is only the teaser! Im curious as hell to see what you did! Very cool Brad! Thanks for keeping it out there!



Coming, coming


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## bitzer (Nov 11, 2009)

blsnelling said:


> Coming, coming



I don't mean to rush ya1 You've just kept us hangin for days LOL!

After doing this would you give any creedance to the statement below. I've spent a lot of time trying to understand the theory of the strato. 

"What I'm thinking is that the EPA is after controlling unburnt hydrocarbons emmisions, by the addition of extra air from the strato ports it casues a more efficient burn of the mix." 

I came up with that thought after seeing the saws reaction when the strato ports were closed off after I undid the throttle linkage to them.


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## stihlboy (Nov 11, 2009)

opcorn: good job brad...... id like to see you get a spare p&c in line for a 362 and port it more aggressively, i bet you would also see better results if it had a different carb....... where is andyshine77? hmmm


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## blsnelling (Nov 11, 2009)

I sat and stared at this P&C for a good long while trying to decide what I wanted to do with it. In the end, I basically treated it like any other saw. The only thing the strato really does is add that extra puff of fresh air to help push out the exhaust. I also believe I can explain why WOT tuning RPMs are not that high, and why it can't be pushed as far/hard as a 361. 

Look at the intake port. It's only about half the width of a normal intake. It's limited by the pockets in the piston that carry the strato charge. All fuel comes through that one small intake port. So it only stands to reason that it can't flow what a traditionally ported engine can. I was able to widen it a little, but not much. I did lower it 4°, but it would need a lot more width to do more. The intake and carb are matched accordingly. So those are bottle necks as well.

Here are the beginning and final port timing numbers.

Exhaust 103° - 100°
Transfers 131° - 124°
Intake 73° - 77°

As you can see, I raised the transfers a lot. I also widened the rear ones. Transfer flow is needed to maintain RPMs in the cut, so they had to come up considerably.

The exhaust was a little low stock, but I don't like to raise it much. I build for torque and compression is your friend.

Now for the pics.

Here's the tiny intake. You can see where the edge of the skirt rides. I went as wide as I could.







I widened the exhaust a TON. I went a full 70%, as measured along the curve. I wouldn't doubt that I widened it at least 3/8"!











I widen it at the flange as well and taper it all the way in.






I raised the tranfers a lot as well. They were really low to begin with at 131°.











On the strato ports, I only slightly widened them. I did very little to them.


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## blsnelling (Nov 11, 2009)

You can see the widened intake here, as well as a little flow work I did in the strato port. Again, I did very little to the strato part of the cylinder.


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## blsnelling (Nov 11, 2009)

stihlboy said:


> opcorn: good job brad...... id like to see you get a spare p&c in line for a 362 and port it more aggressively, i bet you would also see better results if it had a different carb....... where is andyshine77? hmmm



I'v already ported this cylinder nearly as aggressivey as I have any saw. It is what it is. I'm not interested in swapping carbs. The linkage setup is unlike anything you've seen before. If that's what you want, you need a 361. This saw responded very well to the mods and is a great running saw. The fact that a 361 is a little faster in some situations, does not affect the credibility of the 362. It's a great saw.


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## blsnelling (Nov 11, 2009)

stihlboy said:


> where is andyshine77? hmmm



At work.


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## stihlboy (Nov 11, 2009)

blsnelling said:


> I'v already ported this cylinder nearly as aggressivey as I have any saw. It is what it is. I'm not interested in swapping carbs. The linkage setup is unlike anything you've seen before. If that's what you want, you need a 361. This saw responded very well to the mods and is a great running saw. The fact that a 361 is a little faster in some situations, does not affect the credibility of the 362. It's a great saw.



no no no i mean to mess with the strato portion of the cyl.... if only the second butterfly had a jet spraying fuel into it only at wot it would be ideal for a little shot of nitrous


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## stihlboy (Nov 11, 2009)

blsnelling said:


> At work.



better question is wher is his saw? lol


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## FATGUY (Nov 11, 2009)

Don't forget, they were neck and neck in smaller (but still substancial) sized wood.


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## stihlboy (Nov 11, 2009)

FATGUY said:


> Don't forget, they were neck and neck in smaller (but still substancial) sized wood.



man i wish you guys would have tested it in a 6'',8'' 10'',16'' it would show its powerband 






















i have all those sizes in various types of wood.............even a 3'' oak cant


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## blsnelling (Nov 11, 2009)

stihlboy said:


> man i wish you guys would have tested it in a 6'',8'' 10'',16'' it would show its powerband
> 
> i have all those sizes in various types of wood.............even a 3'' oak cant



I don't know what that would have shown that we didn't already show. We compared them in about 12" wood and then buried the bars.


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## blsnelling (Nov 11, 2009)

Some of you are loosing sight of what we're doing here. I ported a 362 and compared it to a stock one. *It saw 18%-26% gains*. Those are respectable gains for a woods port on any saw. The ultimate question here was how does the 362 take to mods. The answer is, *very well*.


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## FATGUY (Nov 11, 2009)

blsnelling said:


> Some of you are loosing sight of what we're doing here. I ported a 362 and compared it to a stock one. *It saw 18%-26% gains*. Those are respectable gains for a woods port on any saw. The ultimate question here was how does the 362 take to mods. The answer is, *very well*.



:agree2: Absolutely, Brad, you were 100% succesful here, good job. I'm sure Blood will be thrilled.


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## stihlboy (Nov 11, 2009)

blsnelling said:


> I don't know what that would have shown that we didn't already show. We compared them in about 12" wood and then buried the bars.



im betting in small as in 6'' that 362 would own the 361..........on a side note was the 362 8 or 7 pin? if its 8 i bet it would do real good with a 7


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## blsnelling (Nov 11, 2009)

stihlboy said:


> im betting in small as in 6'' that 362 would own the 361..........on a side note was the 362 8 or 7 pin? if its 8 i bet it would do real good with a 7



I always run a 7-pin on a 60cc saw. They'll pull an 8-pin but not as well. Perhaps Andy was right, and I should have left the 361 out of this. This is ultimately about how the 362 responds to mods. I was just trying to answer to question in everyone's mind.


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## stihlboy (Nov 11, 2009)

blsnelling said:


> Some of you are loosing sight of what we're doing here. I ported a 362 and compared it to a stock one. *It saw 18%-26% gains*. Those are respectable gains for a woods port on any saw. The ultimate question here was how does the 362 take to mods. The answer is, *very well*.



that was directed at me wasn't it 




so larger wood= larger gain yes?
if so that is a very good sign indicating a great increase in torque in the mid range


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## stihlboy (Nov 11, 2009)

blsnelling said:


> I always run a 7-pin on a 60cc saw. They'll pull an 8-pin but not as well. Perhaps Andy was right, and I should have left the 361 out of this. This is ultimately about how the 362 responds to mods. I was just trying to answer to question in everyone's mind.



i thank you for that because it shows that it is not a very shabby saw.

what all is done to the 361? point being is if it were apples to apples would it be different?

brad, great work as always!


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## FATGUY (Nov 11, 2009)

stihlboy said:


> im betting in small as in 6'' that 362 would own the 361..........on a side note was the 362 8 or 7 pin? if its 8 i bet it would do real good with a 7



I see where you're going with this but it's a bit of a moot point. A 346 would hand both of those saws there ass in 6" wood. Most of the cutting the 60 cc saws will do will be in the 10"-18" range.


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## Fastcast (Nov 11, 2009)

blsnelling said:


> Some of you are loosing sight of what we're doing here. I ported a 362 and compared it to a stock one. *It saw 18%-26% gains*. Those are respectable gains for a woods port on any saw. The ultimate question here was how does the 362 take to mods. The answer is, *very well*.




BTW....Those Stihls did sound damn good! 

Did I actually say that...lol


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## Tzed250 (Nov 11, 2009)

blsnelling said:


> I always run a 7-pin on a 60cc saw. They'll pull an 8-pin but not as well. Perhaps Andy was right, and I should have left the 361 out of this. This is ultimately about how the 362 responds to mods. I was just trying to answer to question in everyone's mind.




Your first intent was the right one. No saw runs in a vacuum. All facts are related. The 441 and 576 will be directly compared to the 440 and 372.

Of course it matters what the gains are, but across the field comparisons are inevitable. 


.


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## stihlboy (Nov 11, 2009)

FATGUY said:


> I see where you're going with this but it's a bit of a moot point. A 346 would hand both of those saws there ass in 6" wood. Most of the cutting the 60 cc saws will do will be in the 10"-18" range.



true because at that point it is not loading the engine its all about chain speed and top end holding rpm..........

so if you slapped a 20+inch bar on these 362's the ported saw would have an even greater percentage in improvement right???


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## FATGUY (Nov 11, 2009)

stihlboy said:


> true because at that point it is not loading the engine its all about chain speed and top end holding rpm..........
> 
> so if you slapped a 20+inch bar on these 362's the ported saw would have an even greater percentage in improvement right???



I would have to agree 100%. The more load you put on the saws, the greater the difference will be between the stock and the ported one. That being said, if you push them so far that their rpms drop dramaticaly then all bets are off.


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## bitzer (Nov 11, 2009)

blsnelling said:


> I sat and stared at this P&C for a good long while trying to decide what I wanted to do with it. In the end, I basically treated it like any other saw. The only thing the strato really does is add that extra puff of fresh air to help push out the exhaust. I also believe I can explain why WOT tuning RPMs are not that high, and why it can't be pushed as far/hard as a 361.
> 
> Look at the intake port. It's only about half the width of a normal intake. It's limited by the pockets in the piston that carry the strato charge. All fuel comes through that one small intake port. So it only stands to reason that it can't flow what a traditionally ported engine can. I was able to widen it a little, but not much. I did lower it 4°, but it would need a lot more width to do more. The intake and carb are matched accordingly. So those are bottle necks as well.
> 
> ...



Thats pretty much what I did on my 455. The intake was actually a perfect circle and very small. I widened as much as I could and lowered it. The exhaust was also tiny and I widened a lot and raised some. The bottom of the transfers I rasied and the top I raised and pointed up and back. I still believe the strato air is needed for combustion. When that port was closed off the saw was WAY rich all the way to the needle 1/2 turn out (from max out 2.5 turns). I don't buy the sweeping of the piston with strato air. I just don't think it would do anything to control unburnt hydrocarbons (trying to think of it from the EPA point of view). I bet all that transfer work was a mother tho. As always very cool pics and work Brad!


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## Maldeney (Nov 11, 2009)

Very interesting design....... Not seeing it in person myself, I would think that the "strato" port and extra air would be for assitance with complete combustion. It is one of those things that I would have to hold in my hands and stare at for hours to try and get inside "it's" head. 

+1


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## blsnelling (Nov 11, 2009)

Maldeney said:


> It is one of those things that I would have to hold in my hands and stare at for hours to try and get inside "it's" head.
> 
> +1



I'm with you on that!!!


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## Curlycherry1 (Nov 11, 2009)

Maldeney said:


> Very interesting design....... Not seeing it in person myself, I would think that the "strato" port and extra air would be for assitance with complete combustion. It is one of those things that I would have to hold in my hands and stare at for hours to try and get inside "it's" head.



Does anyone know who came up with the strato design, specifically who might own the patents? The patents will have background information about what it is supposed to do and why. It may not be detailed but it could end a lot of speculation. Then again, no speculation = no fun.


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## Maldeney (Nov 11, 2009)

Curlycherry1 said:


> Does anyone know who came up with the strato design, specifically who might own the patents? The patents will have background information about what it is supposed to do and why. It may not be detailed but it could end a lot of speculation. Then again, no speculation = no fun.



A guy named Strato! :greenchainsaw:

Did I get the Million dollar question right?


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## blsnelling (Nov 11, 2009)

Curlycherry1 said:


> Does anyone know who came up with the strato design, specifically who might own the patents?



Wasn't it Redmax, and that's why Husky bought them? I may have that all wrong though, lol.


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## kevlar (Nov 11, 2009)

I believe Red Max first came up with the technology.


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## Curlycherry1 (Nov 11, 2009)

kevlar said:


> I believe Red Max first came up with the technology.



I searched Red Max, Redmax, and husqvarna and all I am seeing is a lot of sewing machine patents under husqvarna. I see a design patent for an inlet manifold but design patents are nothing more than pretty pictures.


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## Philbert (Nov 11, 2009)

Curlycherry1]Does anyone know who came up with the strato design . . .[/QUOTE]
[QUOTE=Maldeney said:


> A guy named Strato!




I don't know. But the 'guys' (I'm assuming a variety of different engineers have worked on this) could be termed '_Stato-various_ virtuosos!"

Philbert


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## blsnelling (Nov 11, 2009)

Philbert said:


> I don't know. But the 'guys' (I'm assuming a variety of different engineers have worked on this) could be termed '_Stato-various_ virtuosos!"
> 
> Philbert



I think Bach worked with them as well.


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## Maldeney (Nov 11, 2009)

Thought for sure I won the Million dollars!


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## stihlboy (Nov 11, 2009)

http://www.poweruplawncare.com.au/zenoah/strato_charged.html


you are welcome


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## Philbert (Nov 11, 2009)

blsnelling said:


> I think Bach worked with them as well.



Well of course, _you_ like Bach, because you are always trying to get your engines in tune . . . 

(sorry - I'll stop with that one)

Philbert


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## stihlboy (Nov 11, 2009)

Maldeney said:


> Thought for sure I won the Million dollars!



maybe you aren't such a bad guy after all ill rep ya positive when i can


----------



## Curlycherry1 (Nov 11, 2009)

Yuk, yuk, yuk, you guys crack me up! Anyway, while you were playing 3 Stooges I found some patents by Stihl.

These two seem to be pretty key and explain a lot of what is going on.

US 6,571,756 and this one is more of the same but easier to make 6,598,568.

Bottom line it is all about the cleaner combustion baby, combustion!


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## stihlboy (Nov 11, 2009)

Curlycherry1 said:


> Yuk, yuk, yuk, you guys crack me up! Anyway, while you were playing 3 Stooges I found some patents by Stihl.
> 
> These two seem to be pretty key and explain a lot of what is going on.
> 
> ...



hey genious!  click on the link i posted


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## blsnelling (Nov 11, 2009)

stihlboy said:


> hey genious!  click on the link i posted



Back off Fred.


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## blsnelling (Nov 11, 2009)

stihlboy said:


> http://www.poweruplawncare.com.au/zenoah/strato_charged.html









As quoted from Zenoah's website. BTW, Redmax uses Zenoah engines.

_Zenoah is the first company in the world to achieve extremely low emission two-cycle engines. They have named this engine the Strato-Charged™ engine. 2-cycle engines have a simple structure, and are light and compact. However, due to their structure, about 30% of the mixture gas is not burned (unburned mixture gas) and is discharged as emission gas. There are various barriers that hamper the attainment of reduced emission for 2-cycle engines including a weight increase, larger engines and reduced ease of maintenance. 

By employing a revolutionary engine air intake and scavenging system, this engine makes it possible to greatly reduce the unburned mixture gas. At the same time, it also has the effect of reducing emission gas to give cleaner exhaust. 
Fresh air, which flows into the cylinder from the innovative air inlet port, expels the burnt gas so the mixture gas isn't depleted and is used effectively for the next combustion cycle. The newly designed combustion chamber and spark plug positioning ensure highly stable combustion without miss-firing and clean exhaust at 1/3 of the previous level. This new engine is named "Strato-charged™ engine" after the Zenoah original stratified scavenging engine without a catalytic converter. 

Features of Innovative Zenoah StratoCharged™ engine are: 
Low emission
Low fuel consumption
Low noise 
Low exhaust gas odor and 
High power comparing to our current models of the same displacement. _


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## gink595 (Nov 11, 2009)

So what did you do with the muffler, or did miss that part? are those cats on the 362's??


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## blsnelling (Nov 11, 2009)

You can see that the pocket in the piston doesn't actually "carry" the fresh air charge. I simply creates a passage way for the fresh air to get into the the transfers, ahead of the fuel charge. That way fresh air is being used to purge the exhaust, rather than fuel mix.


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## parrisw (Nov 11, 2009)

blsnelling said:


> You can see that the pocket in the piston doesn't actually "carry" the fresh air charge. I simply creates a passage way for the fresh air to get into the the transfers, ahead of the fuel charge. That way fresh air is being used to purge the exhaust, rather than fuel mix.



Very good design I say, clever whoever thought of it. I can't see how it would hinder performance.


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## blsnelling (Nov 11, 2009)

gink595 said:


> So what did you do with the muffler, or did miss that part? are those cats on the 362's??



Sorry, but I failed to get any pics of the modded muffler. The muffler is made of extremely hard stainless steel. It's much harder to drill and grind than any muffler I've seen before. There is no cat. There is no cage. The muffler is hollow, with the exception of a pipe. The pipe has holes in it, which then exits the side of the muffler. The pipe can be accessed from the mounting flange opening. I cut the pipe fully open. I also added a Husky deflector to the left side, as when holding the saw. I made the hole the full size of the deflector and used a spark arrestor screen, which reduces the area somewhat.


----------



## Philbert (Nov 11, 2009)

OK, in simple words, which part of the 2-cycle process is the 'scavenging system'? Is this just the fresh air/fuel mixture helping to flush the exhaust out?

Thanks.

Philbert


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## blsnelling (Nov 11, 2009)

parrisw said:


> Very good design I say, clever whoever thought of it. I can't see how it would hinder performance.



The only thing hindering performance is the tiny intake port. The fuel charge still comes through this port in its entirety. It can't be made any wider because of the strato cavities in the sides of the piston. And even if you could widen the port significantly, the carb and intake tract are small as well.


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## Maldeney (Nov 11, 2009)

Very Interesting for sure!


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## parrisw (Nov 11, 2009)

blsnelling said:


> The only thing hindering performance is the tiny intake port. The fuel charge still comes through this port in its entirety. It can't be made any wider because of the strato cavities in the sides of the piston.



Yes, but I'm sure a saw could be designed with that in mind. I was talking Strato in general, not just the 362.


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## blsnelling (Nov 11, 2009)

parrisw said:


> Yes, but I'm sure a saw could be designed with that in mind. I was talking Strato in general, not just the 362.



I would have to agree with you then. They would just have to position the strato ports, and corresponding piston cavities such to allow more intake.

But now I'll play devils advocate with myself. Since fresh air is being used to purge the exhaust from the cylinder, perhaps less fuel mix is needed to fill the combustion chamber with the same amount of charge.


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## Tzed250 (Nov 11, 2009)

blsnelling said:


> I would have to agree with you then. They would just have to position the strato ports, and corresponding piston cavities such to allow more intake.
> 
> But now I'll play devils advocate with myself. Since fresh air is being used to purge the exhaust from the cylinder, perhaps less fuel mix is needed to fill the combustion chamber with the same amount of charge.



Have you calculated the area of the main intake+strat intake and compared that to a 361?

A two-stroke has to have the correct stoichiometric ratio no matter what. The 361 would need more fuel, because it looses some out the exhaust. The 362 only looses air. 


.


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## blsnelling (Nov 11, 2009)

No I have not. I'll leave that to our mathematician, Timberwolf,lol


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## constantine (Nov 11, 2009)

Tzed250 said:


> Your first intent was the right one. No saw runs in a vacuum. All facts are related. The 441 and 576 will be directly compared to the 440 and 372.
> 
> Of course it matters what the gains are, but across the field comparisons are inevitable.
> .



OK, so now I'm really interested. Has anyone done a porting job on a 441? Thinking of getting an aftermarket cylinder and practicing on it. Bailey's has the OEM part for $350 - which is more that I want to spend on a "practice" piece. Are there aftermarket cylinders available for the MS 441?


----------



## Curlycherry1 (Nov 11, 2009)

stihlboy said:


> http://www.poweruplawncare.com.au/zenoah/strato_charged.html
> 
> you are welcome



Looks like Zenoah patented the original design:
http://www.google.com/patents/about?id=G3sHAAAAEBAJ&dq=Zenoah

Then Stihl seems to have come out with a blizzard of patents soon thereafter with the same design (they even use the same drawings) and some modifications so that manufacturing could be done efficiently. I wonder if Zenoah sold the basic design or if Stihl raided the idea? Not sure but it does look like Stihl seems to be patenting all the latest modifications. They cite the Zenoah patent a lot and a citation search of the Zenoah patent dumps right into the Stihl patents.


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## stipes (Nov 11, 2009)

*Bard,,gonna ask somthing stupid to ya...*



blsnelling said:


> The only thing hindering performance is the tiny intake port. The fuel charge still comes through this port in its entirety. It can't be made any wider because of the strato cavities in the sides of the piston. And even if you could widen the port significantly, the carb and intake tract are small as well.



There anyway a person can trow the carb on a mill or jig bore and open it up some??? Would that help ???


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## bitzer (Nov 11, 2009)

I emailed Husky and Stihl for an explaination on strato design. Husky was the first to get back to me with this video. Very interesting! This engine is on the Husky 455/460. I can't get the vid on here. It was sent to my email as an attachment. Anyone know how I could get it on here?


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## Tzed250 (Nov 11, 2009)

.


See the Stihl video here.


.


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## shwinecat (Nov 11, 2009)

Brad could you clarify. You had 26% at the smaller wood and 18% on the larger wood. This gave me the impression it did not have as much torque when the bar was buried. If I understood you correctly you indicated this was due to the IYO to a smaller intake. Stihlboy got me confused by larger gain in larger wood. I was thinking the opposite.

Awesome thread!!!! If I have to pay for what I have learned in this thread with beer you are going to be an alcoholic. I am sure Fatguy can help with the beer part of it. 

Thanks, Brad


----------



## ShoerFast (Nov 11, 2009)

Philbert said:


> Well of course, _you_ like Bach, because you are always trying to get your engines in tune . . .
> 
> (sorry - I'll stop with that one)
> 
> Philbert





stihlboy said:


> hey genious!  click on the link i posted





blsnelling said:


> As quoted from Zenoah's website. BTW, Redmax uses Zenoah engines.
> 
> _Zenoah is the first company in the world to achieve extremely low emission two-cycle engines. They have named this engine the Strato-Charged™ engine. 2-cycle engines have a simple structure, and are light and compact. However, due to their structure, about 30% of the mixture gas is not burned (unburned mixture gas) and is discharged as emission gas. There are various barriers that hamper the attainment of reduced emission for 2-cycle engines including a weight increase, larger engines and reduced ease of maintenance.
> 
> ...



+1 Gotcha 

+1 Gotcha 

+1 Gotcha 

Glad to hear that the Strato port is not there for looks, that it has a real function, but fallowing the thread, I like my 361 even more now that it has competition! 

Thanks Brad


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## blsnelling (Nov 11, 2009)

shwinecat said:


> Brad could you clarify. You had 26% at the smaller wood and 18% on the larger wood. This gave me the impression it did not have as much torque when the bar was buried. If I understood you correctly you indicated this was due to the IYO to a smaller intake. Stihlboy got me confused by larger gain in larger wood. I was thinking the opposite.
> 
> Awesome thread!!!! If I have to pay for what I have learned in this thread with beer you are going to be an alcoholic. I am sure Fatguy can help with the beer part of it.
> 
> Thanks, Brad



You are correct. Fred had it backwards. It would appear to me that the strato design is not feeding as much fuel under max load. The 361 and 362 were neck and neck in the smaller wood. Once you bury the bars, you can lean on the 361 significantly harder. I'm still very pleased with an 18% gain with the bar buried. Remember, this the technology that everyone's been afraid of for the last how many years, saying that it wouldn't take to mods well. I say we've proven that wrong. Slingr did a 441 and got good gains as well. I did one of the little Ryobi 10532 (Redmax GZ400), which is a strato, and it flat hauls.


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## Philbert (Nov 11, 2009)

bitzercreek1 said:


> I emailed Husky and Stihl for an explaination on strato design. Husky was the first to get back to me with this video. Very interesting! This engine is on the Husky 455/460.



The file that bitzercreek sent me is 12MB - the A.S. size limit for .avi files is 300KB, so it is about 40X too big to post.

I posted it on YouTube (my first!):

Strato Animation 460 XTORQ
http://www.youtube.com/watch?v=IY7zQKw4qsQ
If you like it, please send rep to bitzercreek as he found it.

Philbert


<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/IY7zQKw4qsQ&hl=en&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/IY7zQKw4qsQ&hl=en&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>


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## Freehand (Nov 11, 2009)

Nice post Philbert,awesome animation...Props to Bitzercreek as well....opcorn:


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## bitzer (Nov 11, 2009)

Philbert said:


> The file that bitzercreek sent me is 12MB - the A.S. size limit for .avi files is 300KB, so it is about 40X too big to post.
> 
> I posted it on YouTube (my first!):
> 
> ...


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## Wild Knight (Nov 11, 2009)

I've always heard that once the major bottleneck is removed, rule of thumb is that changes to ports and transfers henceforth should be made proportional to each other. How far you widen the exhaust should be proportional (not necessarily 1:1) to how far you open the intake, or overall flow through the 'air pump' is disrupted. Since the bottleneck of the intake port could not be alleviated, how does widening the exhaust so much affect this rule of thumb? 

Do you think overall flow can be increased by forcing a greater strato charge?


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## blsnelling (Nov 11, 2009)

Wild Knight said:


> Do you think overall flow can be increased by forcing a greater strato charge?



I'm hesitant to do that since there's no fuel with it.


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## bitzer (Nov 11, 2009)

I don't really see how more flow could be induced by a greater strato charge. I would think less strato charge if anything. More fuel, faster to where it needs to be.


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## Erick (Nov 11, 2009)

Wild Knight said:


> I've always heard that once the major bottleneck is removed, rule of thumb is that changes to ports and transfers henceforth should be made proportional to each other. How far you widen the exhaust should be proportional (not necessarily 1:1) to how far you open the intake, or overall flow through the 'air pump' is disrupted. Since the bottleneck of the intake port could not be alleviated, how does widening the exhaust so much affect this rule of thumb?
> 
> Do you think overall flow can be increased by forcing a greater strato charge?





blsnelling said:


> I'm hesitant to do that since there's no fuel with it.




Brad, as you well know I'm more of a "teach a man to fish" kinda guy... so with said.... stop and think about all you have learned in this thread. 

What are you trying to accomplish by porting a saw to begin with???

What is the optimal fuel to air ratio???

What happens when you disable the strato linkage??? 

So then why is the mixture right when the strato ports are working?

Where does the extra air come from to lean out the mixture to the optimal level???

Why should the tiny (by standard two stroke measures) intake port be a bottleneck???

Why does your saw not turn as many RPMs???

Where do the RPMS come from when you do a standard two stroke???

:dunno:  


Like I said before you're getting better at this and the reason for that is you are starting to figure out why you do what you do and what effect it has when you do it...... Think about what you're doing here. 


BTW nice job... took some nuts to just throw it out there like that unsure of the result.... on someone else’s saw even  NUTS.


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## gonecountry (Nov 11, 2009)

*Wild idea proably won't work*

This is just an idea and there maybe a problem with it that someone will have to point out but here it goes.

What if your were to widen the intake port some? Yes it would allow the mixture charge to go into the strato cavites and then on out through the exhaust but thats no different than a conventional two-stroke. But when the piston is at TDC and the mixture is flowing into the crank case it would have a wider port to flow through.

Is there any reason that the fuel mix going into those cavaites would actually cause any harm?

Thanks Jon


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## bitzer (Nov 11, 2009)

gonecountry said:


> This is just an idea and there maybe a problem with it that someone will have to point out but here it goes.
> 
> What if your were to widen the intake port some? Yes it would allow the mixture charge to go into the strato cavites and then on out through the exhaust but thats no different than a conventional two-stroke. But when the piston is at TDC and the mixture is flowing into the crank case it would have a wider port to flow through.
> 
> ...




The problem I can see with that is that the intake would never close as it would never be sealed by the intake skirt.


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## blsnelling (Nov 11, 2009)

Erick said:


> Brad, as you well know I'm more of a "teach a man to fish" kinda guy... so with said.... stop and think about all you have learned in this thread.
> 
> What are you trying to accomplish by porting a saw to begin with???
> 
> ...



I *think *what you're saying is...go ahead and let those strato ports flow. Open then up and let the extra fresh air mix with the overly rich fuel charge. Ehhh? So what do you want? 25%-30% gains?


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## Andyshine77 (Nov 11, 2009)

How do strato engines work?

Well the clean air/strato ports create an air buffer, they fill the cylinder with a puff of clean air. 

Remember standard piston ported 2cycle engines run very inefficiently. During each cycle a small, but measurable percentage of raw air/fuel mix is expelled out of the cylinder before the piston can fully seal off the exhaust port. Because a strato engine shoots a bit of clean air into the cylinder, before the fuel enters the cylinder, the expelled material is now simply air.


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## Andyshine77 (Nov 11, 2009)

Philbert said:


> The file that bitzercreek sent me is 12MB - the A.S. size limit for .avi files is 300KB, so it is about 40X too big to post.
> 
> I posted it on YouTube (my first!):
> 
> ...



I guess I'm a little late.


----------



## gonecountry (Nov 11, 2009)

bitzercreek1 said:


> The problem I can see with that is that the intake would never close as it would never be sealed by the intake skirt.



I did think of that but then I thought.. So?

Proably a reason it should be I suppose.


----------



## Erick (Nov 11, 2009)

blsnelling said:


> I *think *what you're saying is...go ahead and let those strato ports flow. Open then up and let the extra fresh air mix with the overly rich fuel charge. Ehhh? So what do you want? 25%-30% gains?





Balance Daniel-san.

Go SLOW, it's to hard to put it back..... grind a little, test a LOT!


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## bitzer (Nov 11, 2009)

blsnelling said:


> I *think *what you're saying is...go ahead and let those strato ports flow. Open then up and let the extra fresh air mix with the overly rich fuel charge. Ehhh? So what do you want? 25%-30% gains?



Brad I think your gains are pretty awesome on this saw as it is, but only further experimentation would tell I guess. The way I'm thinking is that the strato air creates a buffer and it fills in space or a volume of area. That is why there are no increased rpms at WOT because it still takes that long to push that extra air out even with increased mix flow. The strato air is taking up the same amount of space and with more air it might take up more space. I know that some of the strato air mixes with fuel, it would have too, but not all of it does, hence the sweep of the exhaust. I guess without trying one would never know tho.


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## bitzer (Nov 11, 2009)

gonecountry said:


> I did think of that but then I thought.. So?
> 
> Proably a reason it should be I suppose.



I think you would lose velocity and impulse.


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## Andyshine77 (Nov 11, 2009)

blsnelling said:


> You can see that the pocket in the piston doesn't actually "carry" the fresh air charge. I simply creates a passage way for the fresh air to get into the the transfers, ahead of the fuel charge. That way fresh air is being used to purge the exhaust, rather than fuel mix.



Exactly what I was trying to say, I haven't read the whole thread yet.


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## breymeyerfam (Nov 11, 2009)

my question: what would happen if I would install a standard style piston, and manufactured an intake adapter plate that blocks off the strato port. then installed a standard boot and carb... oh and dont forget to widen the intake to 70%!


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## Andyshine77 (Nov 11, 2009)

I think the easy way would be to draw fuel into the strato ports. How to do this I'm not sure.:dunno:

BTW this is a really good thread for the most part.


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## gink595 (Nov 11, 2009)

breymeyerfam said:


> my question: what would happen if I would install a standard style piston, and manufactured an intake adapter plate that blocks off the strato port. then installed a standard boot and carb... oh and dont forget to widen the intake to 70%!



Thats easy... A 361


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## breymeyerfam (Nov 11, 2009)

gink595 said:


> Thats easy... A 361



but with but better filtration!


----------



## bitzer (Nov 11, 2009)

Andyshine77 said:


> I think the easy way would be to draw fuel into the strato ports. How to do this I'm not sure.:dunno:
> 
> BTW this is a really good thread for the most part.



Yeah man, fuel thru the strato ports! Thats the ticket!

We're on the cusp of the future of chainsaw modding!

Thanks again Brad for opening the door!


----------



## Wild Knight (Nov 11, 2009)

Erick said:


> What is the optimal fuel to air ratio???
> 
> So then why is the mixture right when the strato ports are working?
> 
> Where does the extra air come from to lean out the mixture to the optimal level???



Lemme see if I am thinking of this correctly...

The intake is small b/c the total volume of air being pumped is a product of both the strato and the intake charges. The front of the strato scavenging charge pushes out the exhaust charge (and possibly aids combustion of residual hydrocarbons as they go out the exhaust port). The tail end of the strato charge combines with the intake charge, thereby leaning the rich charge coming in from the intake. Since the flows are combined, the intake doesn't need to flow as much as a non-strato cylinder and the intake charge can be a little richer. If this is correct, then it would stand to reason that the strato port needs to be enlarged proportional to the intake port. Also, the exhaust port would need to be enlarged proportional to the combined increase of the strato and intake ports to accommodate the combined charge. Transfers would also have to be matched to the new flow capacity. 

I am curious is the strato is actually the bottleneck. If the strato were conservative, then the mixture would error on the side of rich, whereas if it had too much flow the saw would error on the lean side. Maybe that is why Blood's saw looked like it had been run too rich.


----------



## Erick (Nov 11, 2009)

blsnelling said:


> I *think *what you're saying is...go ahead and let those strato ports flow. Open then up and let the extra fresh air mix with the overly rich fuel charge. Ehhh? So what do you want? 25%-30% gains?



I think I should clarify my thoughts a little, there is only so much air that is needed to scavenge a cylinder ahead of the incoming charge.

When a standard two stroke scavenges the cylinder the incoming charge is mixing with burnt (spent) gasses therefore it must carry with it all of the air (oxygen) it will need for combustion. When the fuel charge enters a strato charged cylinder it is mixing with "open air" which contains it's own oxygen and therefore the incoming charge must be richer than the usual "standard" mixture.

Like I said there is only so much charge that is necessary to effectively scavenge the cylinder.

However if you can get more air into the incoming charge you can add more fuel. You would need to be very careful though to not short-circuit the incoming charge with to much of a "buffer"... fine line to walk there and disaster lurks around every corner.


----------



## Erick (Nov 11, 2009)

Wild Knight said:


> Lemme see if I am thinking of this correctly...
> 
> The intake is small b/c the total volume of air being pumped is a product of both the strato and the intake charges. The front of the strato scavenging charge pushes out the exhaust charge (and possibly aids combustion of residual hydrocarbons as they go out the exhaust port). The tail end of the strato charge combines with the intake charge, thereby leaning the rich charge coming in from the intake. Since the flows are combined, the intake doesn't need to flow as much as a non-strato cylinder and the intake charge can be a little richer. If this is correct, then it would stand to reason that the strato port needs to be enlarged proportional to the intake port. Also, the exhaust port would need to be enlarged proportional to the combined increase of the strato and intake ports to accommodate the combined charge. Transfers would also have to be matched to the new flow capacity.
> 
> I am curious is the strato is actually the bottleneck. If the strato were conservative, then the mixture would error on the side of rich, whereas if it had too much flow the saw would error on the lean side. Maybe that is why Blood's saw looked like it had been run too rich.



Sounds like you've got a pretty good handle on it.


----------



## gonecountry (Nov 11, 2009)

bitzercreek1 said:


> Yeah man, fuel thru the strato ports! Thats the ticket!
> 
> We're on the cusp of the future of chainsaw modding!
> 
> Thanks again Brad for opening the door!



Wouldn't opening the intake so that fuel gets into the strato cavities get more fuel where it should be?


----------



## Taxmantoo (Nov 11, 2009)

gonecountry said:


> Wouldn't opening the intake so that fuel gets into the strato cavities get more fuel where it should be?



Depends on whether it should be in the muffler.

Our two primary goals are to get all the exhaust out of the cylinder and replace it with air/fuel mixed at the proper ratio. 
Once that's achieved, we can think about trying to get more than a full charge in the cylinder, which is hard to do without a big tuned pipe to stuff it back through the exhaust.


----------



## bitzer (Nov 11, 2009)

Wild Knight said:


> Lemme see if I am thinking of this correctly...
> 
> The intake is small b/c the total volume of air being pumped is a product of both the strato and the intake charges. The front of the strato scavenging charge pushes out the exhaust charge (and possibly aids combustion of residual hydrocarbons as they go out the exhaust port). The tail end of the strato charge combines with the intake charge, thereby leaning the rich charge coming in from the intake. Since the flows are combined, the intake doesn't need to flow as much as a non-strato cylinder and the intake charge can be a little richer. If this is correct, then it would stand to reason that the strato port needs to be enlarged proportional to the intake port. Also, the exhaust port would need to be enlarged proportional to the combined increase of the strato and intake ports to accommodate the combined charge. Transfers would also have to be matched to the new flow capacity.
> 
> I am curious is the strato is actually the bottleneck. If the strato were conservative, then the mixture would error on the side of rich, whereas if it had too much flow the saw would error on the lean side. Maybe that is why Blood's saw looked like it had been run too rich.




I think the only problem with that is that the intake can only be widened so much because of the limits of the skirt. It would have to be lowered more to increase mix volume, but by then you could lose velocity.


----------



## ShoerFast (Nov 11, 2009)

Could also be setting up one h311 of a situation to start back-firing and popping if you add fuel to the Strato chamber? From the ground up, it is doing what it is designed to do, low emission power. 

As mentioned, it's cool that the 362 is a clean running saw, sounds like it was well engineered, sips fuel, but might need a lot of extra work to match what a 361 as it was designed from the ground up to just make power? 

The race would be against a 361, for me, I like the idea that there are fewer things that can go wrong with the 361 . 

Look at what could happen down the road with the 362, destructive lean issues are now complicated. Even a slightly lean mixture now might take out the jug on a 362 where the 361 would just not run as well. 

Running in extreme cold or heat and altitude changes might be a slightly harder tune in the 362 compared to the 361 ? Will the 362 be more fuel specific, and do poorly on older mix? 

I'm old school, and never would have thought i would say that the 361 was old school, but it suits my needs better for now! 

It will be interesting what Brad can get out of the 362, and there might be a day that we will really be looking at how much power we can get from a sip of fuel?


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## bitzer (Nov 11, 2009)

gonecountry said:


> Wouldn't opening the intake so that fuel gets into the strato cavities get more fuel where it should be?



I was just kiddin man! I don't think flowing mix thru the strato ports would work, because it wouldn't flow fast enough or get to were its supposed to go. The charges would be fighting each other I think if they did get there.


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## Andyshine77 (Nov 11, 2009)

gonecountry said:


> Wouldn't opening the intake so that fuel gets into the strato cavities get more fuel where it should be?



If you could get the air fuel mixture correct, yes.


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## gonecountry (Nov 11, 2009)

taxmantoo said:


> Depends on whether it should be in the muffler.



Some goes in there in the conventional 2 stroke would it be that much more with this design Im sure some will be traped and burn in the cyl.

Please dont mind my questions I still dont fully understand the strato design yet all I know is from pictures, drawings and animations. If I could actually see one in person I could proably answer a few of my own questions.


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## Andyshine77 (Nov 11, 2009)

bitzercreek1 said:


> I was just kiddin man! I don't think flowing mix thru the strato ports would work, because it wouldn't flow fast enough or get to were its supposed to go. The charges would be fighting each other I think if they did get there.



That's a very good point, especially considering the location of the transfers, it probably wouldn't work very well at all.


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## volks-man (Nov 11, 2009)

blsnelling said:


> I sat and stared at this P&C for a good long while trying to decide what I wanted to do with it. In the end, I basically treated it like any other saw. The only thing the strato really does is add that extra puff of fresh air to help push out the exhaust. I also believe I can explain why WOT tuning RPMs are not that high, and why it can't be pushed as far/hard as a 361.
> 
> Look at the intake port. It's only about half the width of a normal intake. It's limited by the pockets in the piston that carry the strato charge. All fuel comes through that one small intake port.  So it only stands to reason that it can't flow what a traditionally ported engine can. I was able to widen it a little, but not much. I did lower it 4°, but it would need a lot more width to do more. The intake and carb are matched accordingly. So those are bottle necks as well.



sorry for jumping in late again. this is a great thread that is apparently on the cutting edge of modding these new-fangled strato saws. and i appreciate all of your open contributions to AS on modding! 
i can't help wondering.
why wouldn't a hard core saw builder use the strato port for more intake charge? fit an adapter and a conventional carb to feed both the intake and the strato-intake fuel mix. 
i have a hard time wrapping my head around this not being the way to go.
what is the downside?


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## Andyshine77 (Nov 11, 2009)

Most of the fresh air charge gets pushed out of the cylinder anyway, you would simply be wasting fuel. I was just thinking out loud before.lol


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## fredmc (Nov 11, 2009)

All the "strato" does is scavenge exhaust. Why use fresh charge to do this?


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## fredmc (Nov 11, 2009)

ah nevermind...


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## woodgrenade (Nov 11, 2009)

So what would explain the overly rich conditions observed in the top of the cylinder? I don't think it is as simple as "Dirty Orange Bottle Stihl Oil". It was either a tuning mistake, or the saw wasn't being run allowing enough of the secondary (strato) air charge into the engine. Too much fuel, not enough oxygen and you have rich conditions. Does the strato intake only open at certain rpm's or engine temps? Or is it directly connected to the primary intake? I'm just thinking that the saw may have only been run a few times to "test cut" and not in any real world conditions like limbing, felling or cutting firewood with prolonged periods of idling. Just trying to put the strato puzzle pieces together!


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## volks-man (Nov 11, 2009)

Andyshine77 said:


> Most of the fresh air charge gets pushed out of the cylinder anyway, you would simply be wasting fuel. I was just thinking out loud before.lol





fredmc said:


> All the "strato" does is scavenge exhaust. Why use fresh charge to do this?





fredmc said:


> ah nevermind...



so which is it?
does strato scavenge, pull exhaust out, of the cylinder....
or
does it produce a wall of fresh air to stop the intake charge being scavenged?

1: you have a tiny intake.
2: you have to tune rich to compensate for fresh air in the strato.
aside from flow considerations... having everything that is introduced to the combustion chamber be at the proper air/fuel ratio cannot be a bad thing.

not being argumentative, just trying to understand and evolve.


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## rms61moparman (Nov 11, 2009)

Andyshine77 said:


> Most of the fresh air charge gets pushed out of the cylinder anyway, you would simply be wasting fuel. I was just thinking out loud before.lol





Maybe not if you have a resonator pipe pushing it back in there!!!


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## Andyshine77 (Nov 11, 2009)

volks-man said:


> so which is it?
> does strato scavenge, pull exhaust out, of the cylinder....
> or
> does it produce a wall of fresh air to stop the intake charge being scavenged?
> ...



It produces a wall of fresh air, so the waist is clean, aka the escaping air doesn't have any fuel in it. no scavenged involved with strato engines at all.

Like Mike said, you'd need a pipe for that.


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## volks-man (Nov 11, 2009)

Andyshine77 said:


> It produces a wall of fresh air, so the waist is clean, aka the escaping air doesn't have any fuel in it. no scavenged involved with strato engines at all.
> 
> Like Mike said, you'd need a pipe for that.



o.k.
so if that (strato) wall was proper mix laden intake charge and the regular intake pulls a proper intake charge, produced by fitting a conventional carb to feed them both, you would no longer need the over rich carb tuning. 

so like i said, why not port the snot out of the exhaust and drop the squish 
and fit a conventional carb and adapter to the strato as well as the intake?
what is the downside other than regular 2-stroke emmisions and fuel consumption?

idk. just a hard concept for me to avoid trying. after all, this is pretty much uncharted terittory, the sky is the limit!


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## Terry Syd (Nov 11, 2009)

*Husky 450 mods*

Over on the 'Saw Building 101' forum, Rick started a thread on modding his Husky 445 strato. Since it is the little brother to my 450 I jumped in and we have been doing some mods to the 445/450s. Here's a link to the thread -

http://www.arboristsite.com/showthread.php?t=107976

You can follow the various twists and turns as I work through modding the 450. The exhaust has been opened up (including a neat trick with the piston) and I am running a larger carb. The stock carb on the 450 has a 11mm venturi, I am running a 13.5mm venturi carb off of a 570.

My latest torque testing showed up another issue, the strato duration is a bit long for my engine. The intake duration is 144 degrees and the strato duration is 154 degrees. I am now in the process of shortening up the duration of the strato port to try and get it closer to the intake duration of 144 degrees.

Although the exhaust duration is only 150 degrees and the blowdown is only 12 degrees - the saw really revs with the bigger carb and the additional 16 mm strato butterfly. In fact, the stock air filter is a bit restrictive.

I'm coming around to the view that with the bigger carb in conjunction with the extra strato function the stock intake duration is adequate for high revs as this engine can suck air big time through two large ports.

Although I have a bigger carb on the saw, the exhaust is running very clean. I thought that with the bigger carb there would be less depression in the crankcase for the strato function to operate. Not so, the strato function is still doing its job.

This is the early stage on modding stratos and as Brad has proven, the potential is there - we just have to keep tweaking them.


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## blsnelling (Nov 11, 2009)

Not to put a damper on the conversation, but putting a carb on both intakes would be way beyond the scope of a woods port. It just doesn' sound practical to me at all. 

If you look at my pics, I did widen the strato ports some already. Is it possible to flow too much though the strato ports and cause the engine to run too lean? I don't know. If I do another one, I'll probably widen them a little more, but I won't get carried away with it. You have to keep in mind that I can't risk trashing someones new $700 saw. I think Cale will be very please with his 18%-26% gains.

As far as it not turning as many RPMs at WOT, no load, that really doesn't concern me. It's holding the RPMs well in the wood, and that's all that really counts. It would be nice to know why it behaves that way though.


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## blsnelling (Nov 12, 2009)

Terry Syd said:


> Although the exhaust duration is only 150 degrees and the blowdown is only 12 degrees - the saw really revs with the bigger carb and the additional 16 mm strato butterfly. In fact, the stock air filter is a bit restrictive.



12° blowdown? Wow! This 362 had more blowdown than most traditional saws at 31°. I ended up with 24°.


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## Terry Syd (Nov 12, 2009)

*Blowdown*

Yeah, 12 degrees blew me away also. I can't remember working on a two-stroke with only 12 degrees of blowdown. The transfers are up a proud 126 degrees of duration. It's weird, almost as soon as you can see into the exhaust port, you can see the top of the transfers appearing.

My first thought was to lift the exhaust, but I figured I'd wait and see what happened with the exhaust the way I worked it. The piston mod with the extra port area apparently helped to give it sufficient blowdown for the revs I'm getting. I'm sure there is some blackflow of exhaust into the transfers, however the strato function on top of the transfer charge shouldn't be allowing any mixing of the mixture and exhaust.

The transfer ports on the Husky are long tunnels from the front of the engine. The long duration of the transfers coupled with the long narrow transfer tunnels on the Husky allows it all to purge out. It took a while for me to get my head around it. I've just never seen a two-stroke ported like this.


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## SpaayDawg (Nov 12, 2009)

*Supercharged?*

Remember when cars and trucks started coming with fuel injection and everyone said that it was "stupid" and "never work" and now every vehicle is, and it's been proven to produce just as much power (and sometimes more) in racing applications and have fewer emissions? That being said, Strato: It's new, it's weird, but it's here to stay.

When I saw the animations the first thing that came to mind was a supercharger. The exhaust creates a scavenging vacuum in the sides of the piston and then that vacuum pulls fresh air into them when over the cylinder ports. The fact that the engine is getting more air into it than through just the carburetor is a great thing!! The more air that is in the cylinder the more fuel can be put in there as well. That being said because this is a 2-stroke engine and not a Variable Valve Timed 4-stroke with a variable fuel flow rate there is going to be a rich condition at idle, and the strato probably accounts for the lower than we're used to max RPM's. There is probably a "window" in which the strato performs best though.

Because the exhaust flow at idle has a lower velocity than let's say at 10,000 then the amount of air than can be pulled into the piston ports from the strato is going to be lower. By the same account, there must be some limit to the amount of "vacuum" that can be produced in the piston ports by the scavenging exhaust because they are the same size regardless of rpm. the higher the RPM the faster the piston is moving in the cylinder and therefore the strato ports are open for a shorter period of time limiting the amount of air that can be both put into them, and pulled out of them.

I think that more gains are to be had manipulating the strato ports, possibly opening the side ports in the piston allowing for more volume to be moved by the piston? widening the cylinder ports in relation to the exhaust and intake? 

Sorry if I got alittle long winded, I'm just an engineering student that knows enough to get myself into trouble. 

On a side note, does anyone ever see a 3rd piston ring being placed below the strato ports on the piston as to "seal" the fresh air away from the air/fuel that's in the crank?


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## Terry Syd (Nov 12, 2009)

*Strato butterfly*

On the Husky, and I'm sure on the Stihl, there is a throttle linkage to the strato butterfly. The strato port is not open at idle. As you open the throttle to about 1/3 the strato butterfly starts to open.

That's what is interesting about my saw. At idle the duration is a short 144 degrees with only the carburetor flowing. However, at full tilt the duration is opened up to 154 degrees and has more than double the venturi area.


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## stihlboy (Nov 12, 2009)

blsnelling said:


> You are correct. *Fred had it backwards. It would appear to me that the strato design is not feeding as much fuel under max load. The 361 and 362 were neck and neck in the smaller wood.* *Once you bury the bars, you can lean on the 361 significantly harder*. I'm still very pleased with an 18% gain with the bar buried. Remember, this the technology that everyone's been afraid of for the last how many years, saying that it wouldn't take to mods well. I say we've proven that wrong. Slingr did a 441 and got good gains as well. I did one of the little Ryobi 10532 (Redmax GZ400), which is a strato, and it flat hauls.



ok, here is an issue. you need to focus on the 362s' bottom to mid range powerband. it has alot more potential than 18% but this is the first 362 messed with. try to port the strato portion of the cyl and run it richer so it leans out.


hmm i bet that will change after experimentation


good luck my friend, you shall figure it out and get that mid range increase.


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## stihlboy (Nov 12, 2009)

blsnelling said:


> Back off Fred.



sorry it was a long day


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## bitzer (Nov 12, 2009)

*About the premature Carbon build up*

I think the seemingly excessive carbon build up on stratos may be due to the blast of cool strato air to the exhaust gases when the piston sweep occurs. The unburnt hyrdrocarbons then solidify to the piston crown and cylinder head. The way I am thinking is this, when you burn wood in a wood stove or especially an outdoor wood boiler, the smoke contacts the cool outside metal surfaces carbon and other chemicals solidify and stick to the sides forming creosote. Could the shot of cool strato air into the combustion chamber that sweeps it out cool some of the chemicals and possibly the unburnt hydrocarbons enough to solidify and "carbon up" the engine faster? 

Also trying to devise an apparatus to make a carb flow thru the strato ports as well would be very difficult when looking at the postioning of the ports. It would take an enitre re-arrangement of the system otherwise the carb would have to flow up hill to get anything into the strato ports as well. If anything two carbs would work better, but the modifications would be impractical to say the least. The channel that the strato air flows through is also not static like a regular transfer. The strato air uses the cut outs along side of the piston to flow and trying to flow a denser mix charge thru that same channel probably wouldn't work. The gains Brad has gotten already are pretty damn good. As this "science" moves along I am sure more secrets will be uncovered.


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## blsnelling (Nov 12, 2009)

I'm not sure how much cooler it'd be than the fuel charge. Although it does go to the base first.


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## BigJ (Nov 12, 2009)

blsnelling said:


> You can see the widened intake here, as well as a little flow work I did in the strato port. Again, I did very little to the strato part of the cylinder.



Late to this one, but couldn't you have widened a bunch more at the bottom of the intake port? It seems like the strato ports only would interfere with the top 1/4 of the intake. Obviously, you'd end up with an atypical shaped port with radically sloping sides (sort of like a bell shape), but that wouldn't be the first thing thats different about this saw.

Bah...nevermind - I just remembered the piston skirt width was the limiting factor...


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## blsnelling (Nov 12, 2009)

bigj said:


> bah...nevermind - i just remembered the piston skirt width was the limiting factor...



+1


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## bitzer (Nov 12, 2009)

blsnelling said:


> I'm not sure how much cooler it'd be than the fuel charge. Although it does go to the base first.



I'm just trying to figure out where the unburnt hydrocarbons go. They claim none are being released. So is the burn more efficient or are the unburnt H-Carbons left in the engine, or both? I don't know. Just trying to uncover the events and the carbon deposits left over.


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## blsnelling (Nov 12, 2009)

What they're saying is that the fresh fuel charge is not used to expel the exhaust.


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## Maldeney (Nov 12, 2009)

blsnelling said:


> What they're saying is that the fresh fuel charge is not used to expel the exhaust.



I agree .................................................................................................................................. but I still say it also has to help the burn as well. Like was mentioned by in another post when the strato butterfly was disconnected the saw ran way rich.


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## bitzer (Nov 12, 2009)

blsnelling said:


> What they're saying is that the fresh fuel charge is not used to expel the exhaust.



That makes sense to me. I know that not everything in a fresh charge is burned because no burn is 100% efficient so regardless if it is pushed out by air or a fresh mix charge chemicals are being released. Thats just the nature of combustion. I get what you are saying and what they are trying to do. I'm just trying to account for that advanced carbon build up. I've been plagued by the strato for months, ever since I first opened mine. I wish I could hold that 362 cylinder in my hands for a while. 

Does it look like the strato charge could enter all of the transfers from how they are postioned? My cylinder only has two transfers so I know where the strat air is going.


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## Hddnis (Nov 12, 2009)

The strato charge (of air) is almost moot to getting gains from the engine. All it does is fill the cylinder with clean air creating a fuel charge free buffer on each stroke. All things considered it should be left alone to give the little puff of air at the right time.

The gains will come from the standard intake and exhaust and transfer porting that is always done.

Now, that over-simplifies because there will be some interaction between the clean air charge and the fuel-air charge. Timing between those two will also start to factor in. But overall, you can start with mods as if it were a regular two-stroke.



Mr. HE


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## Hddnis (Nov 12, 2009)

The idea of adding fuel to the clean air charge is just going to waste fuel. That charge is blown out the muffler. It would literally be throwing fuel away. Power is how much fuel/air mix you have on the combustion stroke, not how much fuel/air you run through the engine. Like all things, it has to be in the right place at the right time.



Mr. HE


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## Maldeney (Nov 12, 2009)

But not all of the "fresh air" charge will go out of the exhaust. The air is only taking the place of the burnt gases, thus leaving some volume behind to be mixed with the fresh fuel charge. I would think.opcorn:


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## blsnelling (Nov 12, 2009)

Hddnis said:


> The strato charge (of air) is almost moot to getting gains from the engine. All it does is fill the cylinder with clean air creating a fuel charge free buffer on each stroke. All things considered it should be left alone to give the little puff of air at the right time.
> 
> The gains will come from the standard intake and exhaust and transfer porting that is always done.
> 
> ...



That's the approach I took to it. Next time I'll probably go on down to 80° on the intake. I stopped at 77° on this one.


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## Terry Syd (Nov 12, 2009)

*Clean burn*

On my saw the combustion chamber, piston and exhaust is running very clean, so I think this 362 carbon deposits may be related to very rich running during the break-in. 

I also tried disconnecting the strato linkage and found the engine running excessively rich. The strato function is taking a BIG gulp of air, it is not a little puff of air. Heck, my saw came with a 11mm venturi on the carb, but has a 16mm strato butterfly. Couple that with the longer duration of the strato function and it is likely that the strato function is moving more air than the carb.

The idea of running a second carb on the strato port would probably make a good race saw. The race saw would likely have a more radical exhaust timing and would loose a lot more mixture out the exhaust port. If the carb on the strato port was set for a very rich mixture it would be flushing the sides of the piston and the combustion chamber with an extra rich mixture and then that mixture would get blown out the higher exhaust port.

This would allow the saw to run much cooler and could allow some outrageous compression ratios. Essentially, the saw would be more 'liquid' cooled and could handle the higher compression.

I'm going to keep tinkering with my saw. My next mod is to shorten the strato timing and see if I can improve the torque. I'll post the results over in Ricks 445 thread.


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## Hddnis (Nov 12, 2009)

Maldeney said:


> But not all of the "fresh air" charge will go out of the exhaust. The air is only taking the place of the burnt gases, thus leaving some volume behind to be mixed with the fresh fuel charge. I would think.opcorn:




True, which is why I said it really isn't that simple, but is for purposes of porting.

Any clean air left can be compensated for through tuning for the most part.


Mr. HE


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## Hddnis (Nov 12, 2009)

blsnelling said:


> That's the approach I took to it. Next time I'll probably go on down to 80° on the intake. I stopped at 77° on this one.





Yeah, reading through your posts I could see that you did. It might seem simple and I think that some have trouble because strato saws have been made out to be complicated. In some ways they are, but in other ways they are a regular engine with an add-on.

You did good work on this one and are breaking new ground in many ways. Sharing this info will help many of us jumpstart our own experiments with these new engines.


Mr. HE


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## Hddnis (Nov 12, 2009)

Terry, a lot of what you said makes sense from a racing point of view. It makes no sense for a working saw.

By most calculations the strato port will be moving up to a third of the air that goes through the saw. If port timing is right that 'clean' air will not be a major part of the charge in the combustion chamber.



Mr. HE


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## tdi-rick (Nov 12, 2009)

Terry Syd said:


> [snip]
> 
> The idea of running a second carb on the strato port would probably make a good race saw. The race saw would likely have a more radical exhaust timing and would loose a lot more mixture out the exhaust port. If the carb on the strato port was set for a very rich mixture it would be flushing the sides of the piston and the combustion chamber with an extra rich mixture and then that mixture would get blown out the higher exhaust port.
> 
> [snip]



and a well designed pipe would shove that right back into the chamber.

It could very well work as a race setup.


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## Terry Syd (Nov 12, 2009)

*Tuning*

Rick, yeah a pipe on a racer. Here's another one I referred to in the other thread that could be used on a work saw - put a resonator on the strato port.

If the strato port had longer duration than the intake (as mine presetly has), then the blowback into the 'intake' at lower revs would occur in the strato port. Put a tuned intake on the strato port to pack that blowback mixture back into the engine.

The saw would have a short duration intake for idle, a longer duration at WOT, and then when the revs drop in big wood the resonator would compensate for the longer duration and keep the mixture from blowing back.

I'd love to be able to do that, but at this point I'm just going to shorten up the strato timing a bit.

On a race saw it would make a great deal of sense. Run dual carbs and have the longer duration strato port tuned to provide a good boost at the desired RPM. A Helmholtz resonsator can provide something like a 2 psi boost to a two-stroke intake. Couple that with a expansion chamber and the cooler running piston that allows more compression and the stratos are the new trick saw to be running.


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## tdi-rick (Nov 12, 2009)

Terry Syd said:


> [snip]
> A Helmholtz resonsator can provide something like a 2 psi boost to a two-stroke intake. Couple that with a expansion chamber and the cooler running piston that allows more compression and the stratos are the new trick saw to be running.



Geez, that'd be worthwhile with piston porting.

Most of the (little) experience I had was with Rotary and reed valves so no where near the spitback you get with longer intake duration of a piston port.


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## Terry Syd (Nov 12, 2009)

*Timing*

Same here, most of my work on two-strokes is with reed and rotary systems. Heck, a 70 degree closing time on a rotary is fairly high, but for a piston port it is industrial timing.

Like I said above, I am coming around to the idea on my strato that the stock intake timing of 144 degrees (72 degrees ATDC) is going to be adequate. The bigger carb on the intake along with the strato butterfly allows the engine to take a big gulp when everything opens.

The blowback I got in the strato port when torque testing indicated that I might be able to improve the torque if I could move the strato timing of 154 degrees (77 degrees ATDC) back closer to the intake timing. In fact, from looking at the jug (see the 445 thread) it appears that the factory originally had less timing on the strato function.


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## cpr (Nov 21, 2009)

Finally go to the bottom of this one. Great thread and lots of information to boot! I'd rep ya' Brad, but I can't! Great job as per usual. I can't wait for someone to put a 576xpat in your lap! I'd do it if I could swing it right now.


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## blsnelling (Nov 21, 2009)

cpr said:


> Finally go to the bottom of this one. Great thread and lots of information to boot! I'd rep ya' Brad, but I can't! Great job as per usual. I can't wait for someone to put a 576xpat in your lap! I'd do it if I could swing it right now.



I've got a basket case 575 here right now. It came from a tree service, but isn't economical for them to have me repair.


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## ECRUPPRECHT (Dec 4, 2009)

would it be possible to put a 361 top end intake boot carb etc. on the 362 cankcase i noticed a diffrence in the impulse setup as it does not run a line is it a possible swap if some one wanted a new 361 after they are gone??


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## blsnelling (Dec 4, 2009)

ECRUPPRECHT said:


> would it be possible to put a 361 top end intake boot carb etc. on the 362 cankcase i noticed a diffrence in the impulse setup as it does not run a line is it a possible swap if some one wanted a new 361 after they are gone??



The entire saw is completely different.


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## davec (Dec 25, 2009)

Here's some more info on a stock 362, FYI. I've had this about a month now and probably have about 15 hrs of use time on it. "Normal" use as I would consider it, except for the cold weather (10's-20's F) - felling, bucking, limbing hardwoods in the 3-24" dbh range (mostly in the 3-12" range).  

I was cleaning it up and sharpening the chain tonight and decided to pull the spark plug to take a peek inside to see if I saw the running rich issue Brad first posted at the start of the thread. The piston had a couple tiny spots of deposits on the crown - nothing notable. I used regular Stihl orange bottle oil in the first 2 gallons of gas I made (prob 1.5 gals went into this saw) as it was all I could get at first. I switched to the Stihl HP Ultra after that for the next 1+gal of fuel (and from now on). No pics of the piston as I can't get a camera in there close enough to see anything. Carb is set pretty much right at factory settings. Haven't needed to tweak it so far.

Here's what the spark plug looks like too:















Just a bit more info on the saw, FWIW.

-Dave


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## Net-Knight1 (Dec 26, 2009)

By the way...how much have you payed for your 362's?


The Saw is not available in Germany yet, could someone ship it overseas?


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## Wild Knight (Jan 5, 2010)

Nice animation of the strato poritng and air flows. May have been posted elsewhere, but worth reviewing:

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/IY7zQKw4qsQ&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/IY7zQKw4qsQ&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>


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## Philbert (Jan 5, 2010)

Wild Knight said:


> May have been posted elsewhere, but worth reviewing



(Just 5 pages back - page 13, post 181)

Philbert


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## Wild Knight (Jan 5, 2010)

Figures  

Oh well, I saw the video while in the hotsaws forum today, and it made me think of this thread.


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## FATGUY (Jan 5, 2010)

Wild Knight said:


> Nice animation of the strato poritng and air flows. May have been posted elsewhere, but worth reviewing:



awesome video, +1


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## Knuckles (Jan 5, 2010)

davec said:


> Here's some more info on a stock 362, FYI. I've had this about a month now and probably have about 15 hrs of use time on it. "Normal" use as I would consider it, except for the cold weather (10's-20's F) - felling, bucking, limbing hardwoods in the 3-24" dbh range (mostly in the 3-12" range).
> 
> I was cleaning it up and sharpening the chain tonight and decided to pull the spark plug to take a peek inside to see if I saw the running rich issue Brad first posted at the start of the thread. The piston had a couple tiny spots of deposits on the crown - nothing notable. I used regular Stihl orange bottle oil in the first 2 gallons of gas I made (prob 1.5 gals went into this saw) as it was all I could get at first. I switched to the Stihl HP Ultra after that for the next 1+gal of fuel (and from now on). No pics of the piston as I can't get a camera in there close enough to see anything. Carb is set pretty much right at factory settings. Haven't needed to tweak it so far.
> 
> ...



Nice. If you're happy with the way it's running, I wouldn't mess with it. That's about as spot-on as your going to get with 2-stroke ***.


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## Wild Knight (Jan 17, 2010)

Do you think a spark plug in a higher heat range may fix some of the fouling/carbon problems with strato saws?


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## bigredd (Jan 18, 2010)

Looks like this 362 is now for sale. Hard to imagine making any profit reselling a new ported saw.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=380197579522&ssPageName=STRK:MEWAX:IT


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## Hddnis (Jan 18, 2010)

Ok, we can all start putting our bets down what price it will end at.:hmm3grin2orange:



Mr. HE


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## blsnelling (Jan 18, 2010)

bigredd said:


> Looks like this 362 is now for sale. Hard to imagine making any profit reselling a new ported saw.
> 
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=380197579522&ssPageName=STRK:MEWAX:IT



Looks like someone might be in for a free port job at that price


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## stihlboy (Jan 18, 2010)

BloodOnTheIce said:


> Looks good, I can't wait to run it. And no I didn't sell it and it's not for sale.
> And this saw only has a few tanks of gas through it and should pick up a little more when it's got a few hours on it. I didn't have this saw ported to to beat a 361, I wanted to see what could be done w/ this new technology. Thanks again Brad.



 check ebay


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## blsnelling (Jan 18, 2010)

stihlboy said:


> check ebay



That was a while back Fred. He probably saw what he wanted to see and is ready to move on.


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## Country1 (Jan 18, 2010)

Don't know what to make of that??...:monkey:


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## stihlboy (Jan 18, 2010)

blsnelling said:


> That was a while back Fred. He probably saw what he wanted to see and is ready to move on.



next thing you'll get is a 441


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## blsnelling (Jan 18, 2010)

stihlboy said:


> next thing you'll get is a 441



Or a 461, lol.


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## stihlboy (Jan 18, 2010)

blsnelling said:


> Or a 461, lol.



yup they are coming

so is the dolmar 5800 60cc saw :taped:


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## FlyLow (Dec 6, 2011)

BLsnelling: Have you ported any ms362s since this first one? Have you changed how you ported with any other results?


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## blsnelling (Jan 16, 2014)

A very early look at the 362.


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## dl5205 (Mar 11, 2014)

I was glad to see that most of the pics in this old thread survived. Many of our good old pics are lost.


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