# Echo CS-400 Chainsaw Muffler Mods



## Team FAST (Mar 20, 2010)

I modified the muffler on my Echo CS-400 Chainsaw, mostly based on recent recommendations provided by many individuals posting in other threads on this forum. 

However, I thought it might be interesting to quantify the airflow differences of the mods using a Superflow SF-110 flowbench. You can see how the various pieces of the muffler contribute to the airflow results, as well as a direct before/after comparison. The attachments tell the story.

I have a powerpoint file of all these attachements if anyone wants a copy.

Enjoy! Comments welcomed/appreciated.

-erik


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## Team FAST (Mar 20, 2010)

*Echo CS-400 Muffler Mods*

Here's the next five slides in my presentation.


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## Team FAST (Mar 20, 2010)

*Echo CS-400 Muffler Mods*

Here's the last slide!


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## keith811 (Mar 20, 2010)

nice work,

I just drilled a 1/2" hole in the front of my muffler. doesn't look the best but works great. I thought I was going to have to cut out a bunch of stuff from inside the muffler but the only thing in it was one little deflector right under the stock outlet so now the exhaust has a direct outlet square in front of the port..


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## caotropheus (Mar 20, 2010)

Team Fast

Very nice indeed. I like the equipment you used to make the silencer transformations. It is much more exact than using empirical measurements.


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## Hddnis (Mar 20, 2010)

Thanks for sharing that with us. Rep sent.



Mr. HE


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## Terry Syd (Mar 20, 2010)

*Deflector*

Thanks for doing that in depth analysis of the muffler mod and showing us the results. Rep sent.

I note that the flow continued to increase when the deflector was taken off. Perhaps you may want to look at the area of the deflector opening.

When I was doing the calculations on my new 450 Husky, I found that the opening of the deflector was the limiting factor. After I opened up the deflector outlet, the outlet inside the deflector then became the limiting orifice (which was then modified so that the deflector outlet again became the limiting factor).

When I opened up the area inside the deflector I drilled three holes that would direct the flow towards the outlet of the deflector. That was done in an attempt to prevent turbulence inside the deflector which could increase resistance to flow. - Thanks again for the PP presentation.


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## caotropheus (Mar 20, 2010)

After Terry's post, I would like to emphasize that the spark arrest net clogs very easily in Echo saws. Usually fellows around here open it up and let the exhaust gases flow out freely. Take a look at my Echo 341.


http://www.arboristsite.com/showthread.php?t=129486


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## Hddnis (Mar 20, 2010)

The spark screen can clog up, but some of us don't have the option of removing it. 




Mr. HE


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## XJPete87 (Mar 20, 2010)

Nice job.. Love the actual flow bench numbers. How do you guys enlarge the holes internal to the muffler? Do you split the cases? mine are brazed together and seemed like a real PITA to seperate..


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## Team FAST (Mar 20, 2010)

I did split the cases and it was a real PITA. The two halves are furnace brazed together and the factory and there is a spot braze on center of the intenal baffle holding it to the outside can as well. I ended up using a disc sander and sanding off the outer lap seam. Then I had to carefully braze the assembly back together as a butt joint. 

I think the mods could be accomplished without disturbing the outer case assembly. However, enlarging the internal baffle holes like I did might prove difficult.

I chose to provide flow data for each component in the muffler assembly so you can see the redecution from each indivudal piece. I am running it with the screen on, to keep things reasonably safe and forestry compliant.


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## Team FAST (Mar 20, 2010)

caotropheus said:


> After Terry's post, I would like to emphasize that the spark arrest net clogs very easily in Echo saws. Usually fellows around here open it up and let the exhaust gases flow out freely. Take a look at my Echo 341.
> 
> 
> http://www.arboristsite.com/showthread.php?t=129486




I happen to have a CS-341 saw as well (really love it) and I noticed that mine also has a CAT muffler. I also noticed that the Echo CS-3400 has an earlier non-cat muffler which is a bolt on swap. Looks like I'll be doing another flowbench comparison soon


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## malador (Apr 15, 2010)

I subscribed to this forum just so I could see your slides. Nice job! I copied everything you did, plus enlarged the deflector holes. Before the 18” bar was almost more than the motor could handle, not anymore!


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## HLC03 (Sep 3, 2010)

Thats hilarious. I subscribed to arboristsite just to see the slides of this mod as well. Team FAST, NICE JOB! The Echo CS-400 is my first and only chainsaw so far. I love it. I really want to do some mods to the muffler, but all the brazing and welding of stuff is way out of my mechanical reach. What can I do to my CS-400 saw with basic tools and maybe a drill and dremel tool? Can you help me?
Thanks A LOT in advance.
Adam


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## mweba (Sep 3, 2010)

Wish I had toys like that. Would be interesting to see how a competeing manufacturers muffler stacks up against the cat echo.
On my cs-450p the cat sits to one side so bypassing it was easy. Unlike your model which sits in the center. These saws respond well to this mod.


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## malador (Sep 3, 2010)

HLC03 said:


> Thats hilarious. I subscribed to arboristsite just to see the slides of this mod as well. Team FAST, NICE JOB! The Echo CS-400 is my first and only chainsaw so far. I love it. I really want to do some mods to the muffler, but all the brazing and welding of stuff is way out of my mechanical reach. What can I do to my CS-400 saw with basic tools and maybe a drill and dremel tool? Can you help me?
> Thanks A LOT in advance.
> Adam




I didn't split the muffler at first either. Even with doing everything but the split ,I still got a big power increase. You will have to remove the limiter caps aswell. Otherwise the motor is going to run to lean.

*edit* you will need the dremel tool. I mostly used the cutting will and sanding drum.


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## Team FAST (Sep 4, 2010)

I split the muffler as part of the original investigation to see the entire guts in detail. In hindsight, it is not required to spilt the muffler open to remove the Catalytic converter, or open up the outlet at the screen.

I would like to see a CS450 muffler stock to see what Echo did differently. I'd be willing to repeat the experiment if someone could provide the donor. They would get a "Team FAST tuned" muffler in return. 

The purpose of the flowbench measurements was an attempt to quantify the amount of backpressure present in a stock muffler and show the relative gains accomplished by modifying the muffler. Obviously carb tuning was required. It definately wanted more fuel. I think there is more horspower available if the ignition timing curves could be adjusted. 

-erik


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## HLC03 (Sep 4, 2010)

erik,

i'd be more than happy to mail you my cs-400 muffler. the only thing is I need the saw for a job this week. if I sent you the muffler and the funds for quick shipping how fast could you turn it around to me? i'd be willing to add some money in there for your time. let me know. I just need some detailed help after you send it back to me so i can tune the saw, and adjust the air fuel ratio. 

on the other hand I would be also willing to tackle this mod by myself if you could offer detailed info of each step. I can also post pics of the process. thanks for everything,
adam


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## mweba (Sep 4, 2010)

CS-450p muffler. I didn't get the greatest pics at the time. As you can see, the cat looks the same. Just the placement is different.






















I have a 346xp cat muffler floating around. If I find it, I will send it out with all the other stuff I need to get out for other members.


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## Zombiechopper (Sep 4, 2010)

the last slide where it says, "40cc Echo now hangs with 55cc saws!"

You haven't run too many 50cc saws have you? Let me just suggest you change that slide.


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## o8f150 (Sep 4, 2010)

thanks for sharing that info,,as you can see i run echos and i have found myself it makes a big difference to open them up


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## HLC03 (Oct 3, 2010)

Guys,
I just removed the muffler from my CS-400 and am about to fire up my dremel. A couple of questions...
1. Does the Cat need to be cut out? When I cut open the hole on the back of the muffler will that free up the cat to just fall out or does it need to be cut?
2. If the cat needs to be cut out whats the best way?
3. How to I remove the carb caps that someone mentioned to tune the saw? Does this mean just adjust the carb settings on the side of the saw (the ones for idle and high rpm?).

Someone please help me... I'm a noob with this chainsaw and I want it to cook!

Thanks everyone,
Adam


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## PLMCRZY (Oct 3, 2010)

HLC03 said:


> Guys,
> I just removed the muffler from my CS-400 and am about to fire up my dremel. A couple of questions...
> 1. Does the Cat need to be cut out? When I cut open the hole on the back of the muffler will that free up the cat to just fall out or does it need to be cut?
> 2. If the cat needs to be cut out whats the best way?
> ...


Take a drill and drill out the cat then flip it upside down and make sure all the little particles are out.

Limiter caps are easy, take a dry wall screw or something similar and thread them into the cap, now take some pliers or whatever and pry them out. Once removed you can tune your high speed needle and your low speed needle. I recommend richening it up a bit until about 3 or 4 tanks, then lean it out.


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## HLC03 (Oct 3, 2010)

Then how do I adjust the needle settings with a flathead screwdriver?

adam


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## PLMCRZY (Oct 3, 2010)

HLC03 said:


> Then how do I adjust the needle settings with a flathead screwdriver?
> 
> adam



Well ya


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## mountainlake (Oct 4, 2010)

Zombiechopper said:


> the last slide where it says, "40cc Echo now hangs with 55cc saws!"
> 
> You haven't run too many 50cc saws have you? Let me just suggest you change that slide.



My little CS400 with that NK chain cut 1 second faster than my open port Husky Rancher 55 (53cc) . Both with sharp chains. My Rancher 55 is by far my slowest 50cc saw, yes it's tuned good with 150# comp. Let me suggest you run a muff modded tuned right CS400 with a NK chain. Steve


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## PLMCRZY (Oct 4, 2010)

mountainlake said:


> My little CS400 with that NK chain cut 1 second faster than my open port Husky Rancher 55 (53cc) . Both with sharp chains. My Rancher 55 is by far my slowest 50cc saw, yes it's tuned good with 150# comp. Let me suggest you run a muff modded tuned right CS400 with a NK chain. Steve



Sounds like a need to swap my husky 55 for a cs400.......


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## HLC03 (Oct 13, 2010)

*tuning cs400 after muff mod...someone help me please.*

mountainlake and other cs400 aficionados in this thread,

ok.. finally after about 3 weeks of jobs i needed my trusty cs-400 (my only saw) for I decided today when I got home from work to play around with the following thinking that i probably wouldn't be able to finish the mod. i was wrong. I used a dremel tool with a 1 inch regular cut off wheel to open up restrictive small hole before the cat, then i used some wd-40 and a super sh1tty old 1/2" drill bit and a screwdriver and went to town on the catalytic converter. then i polished the 1" chamber that now is open and freed up thanks to removing the cat. i also cut the front out of the muffler where the exhaust holes where and made the hole the same shape as the indentation on the spark arrester screen. then i cut the silver spark arrester plate dome thing off. i basically followed the pictures in this thread to a t. thanks team fast.

this is where i am at now: I need someone to help me tune the H and L needles... should i just follow the manual? or is there some other tuning procedure that I should follow considering that I just majorly opened the saw up on the exhaust side. also... is there any other ways to make this bad boy breathe any better? new carb or air filter element? do they make hi-performance air filters for saws? what kind of chain should i buy and where should i buy it? i know there are a lot of questions but I figure you echo guys can help a brotha out.:chainsawguy::chainsawguy::chainsawguy:

thanks guys!
adam


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## PLMCRZY (Oct 13, 2010)

How many tanks have you ran thru it?

Filter is the best in class, get a non safety chain that will help a bunch.


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## HLC03 (Oct 14, 2010)

i've run about 10 tanks of gas with the stock muffler. i have only been running 89 octane at the lowest and redmax 2stroke oil out of it. i think i should start running 93 with the muffler mod though.

1 more question for TEAM FAST or anyone that has done his cs-400 mod... in slide number 8 it says that you enlarged the 6 internal baffle holes from .25 to .281". how the hell do i get to those baffle holes? do i need to split the muffler and braze it back together? because if thats the case i can not do that i don't have the brazing stuff needed. is there a way to enlarge the 6 baffle holes without the split? Can i still recognize the gains team fast posted with his flowbench that he did without enlarging the baffle holes? how do i do it?


thanks a million,
adam


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## Miles86 (Oct 14, 2010)

Teamfast- your slides are great, thanks! 

I did this mod for my cs-370 except I did not enlarge the baffle holes-(did not want to split the canister open). I did the deflector like teamfast and deleted the spark screen. I got the Kat out by taking a pair of bent-nosed needle nose pliers and just pulled the guts out, it's easy. clean up the burrs with a dremel stone. Flush with hot soapy water.

IMO it's not totally needed to enlarge the baffle holes, my cs-370 is super responsive now and the noise level is no more than stock, maybe the idle sounds a bit different. Use copper coat on the muffler gasket as a dressing to stop exhaust leaks at cylinder. A better chain is the biggest help.


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## HLC03 (Oct 14, 2010)

miles said: IMO it's not totally needed to enlarge the baffle holes, my cs-370 is super responsive now and the noise level is no more than stock, maybe the idle sounds a bit different. Use copper coat on the muffler gasket as a dressing to stop exhaust leaks at cylinder. A better chain is the biggest help.[/QUOTE]

ok thanks, what is copper coat? is it like a loctite kind of paste on stuff? whats the brand name and where can i get it?

thanks,
adam


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## Miles86 (Oct 14, 2010)

HLC03:

Hey, 

it's made by CRC "KW Copper Coat" get the 4 oz. brush top can, not the spray. Shake the can well to mix the product, let it sits for a few minutes to get tacky.


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## HLC03 (Oct 15, 2010)

thanks for the tip on the copper coat... i'm going to pick some up real soon. 

heres my next question though: i just finished painting the muffler with 1200 degree black paint (pics coming soon). how hot do you think that muffler gets? and I really want to know what the best way to tune my saw is. i heard that i need to take a drywall screw to pull the caps off the needles. i have run about 10 tanks of 89octane with redmax 2stroke mix out of the saw since it was purchased new last summer and i put sta-bil fuel stabilizer in there in the winter. I am going to switch to 93 octane today and run nothing but 93 out of the saw from now on. my question is... How do I tune the saw? Do I just tune it the way it says to in the echo manual? can someone help me with a high performance carb tune?

thanks guys,
adam:chainsawguy:


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## GTP (Oct 15, 2010)

I did this same procedure on my CS-400 this week. I did not enlarge the baffle holes either as I did not want to split the case. The cat was a little bit harder to get out than I originally thought but used needle nose pliers, screw driver and a drill with an old large bit to get the cat and material out. I can't believe how restrictive that must have been !

It's raining here but I am going to get it into some wood and tune it asap.


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## GTP (Oct 15, 2010)

HLC03 said:


> thanks for the tip on the copper coat... i'm going to pick some up real soon.
> 
> heres my next question though: i just finished painting the muffler with 1200 degree black paint (pics coming soon). how hot do you think that muffler gets? and I really want to know what the best way to tune my saw is. i heard that i need to take a drywall screw to pull the caps off the needles. i have run about 10 tanks of 89octane with redmax 2stroke mix out of the saw since it was purchased new last summer and i put sta-bil fuel stabilizer in there in the winter. I am going to switch to 93 octane today and run nothing but 93 out of the saw from now on. my question is... How do I tune the saw? Do I just tune it the way it says to in the echo manual? can someone help me with a high performance carb tune?
> 
> ...



Adam check out this thread on tuning. Brad even posts a good video.
http://arboristsite.com/showthread.php?t=113538


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## HLC03 (Oct 16, 2010)

GTP said:


> Adam check out this thread on tuning. Brad even posts a good video.
> http://arboristsite.com/showthread.php?t=113538



hey thanks for the link and rep power comin' your way. 

i wanted to let you guys following this thread know that i completed the mod and put the copper coat on both sides of the gasket, put the muffler back on, added some 93 octane fuel and started her up this afternoon. i haven't tuned her yet or run her through any wood but damn, when i rev it the saw wants to raise the bar up. it seems like it really made a huge difference. i will post when i get it tuned and into some wood. btw, i also polished the muffler port pretty good and shinny.

best of luck with your mods,
adam


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## GTP (Oct 16, 2010)

HLC03 said:


> hey thanks for the link and rep power comin' your way.
> 
> i wanted to let you guys following this thread know that i completed the mod and put the copper coat on both sides of the gasket, put the muffler back on, added some 93 octane fuel and started her up this afternoon. i haven't tuned her yet or run her through any wood but damn, when i rev it the saw wants to raise the bar up. it seems like it really made a huge difference. i will post when i get it tuned and into some wood. btw, i also polished the muffler port pretty good and shinny.
> 
> ...



I am getting mine together and tuning this weekend. I'll post here on my findings as well.


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## PLMCRZY (Oct 16, 2010)

Def. gonna give my 370 a work out tmrw. Hopefully ill get it tuned just right, that safety chain needs to go though!


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## GTP (Oct 17, 2010)

ClayKann101 said:


> Def. gonna give my 370 a work out tmrw. Hopefully ill get it tuned just right, that safety chain needs to go though!



Did you check out the Baileys Kerf bar and 20NK chain combos!


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## PLMCRZY (Oct 22, 2010)

GTP said:


> Did you check out the Baileys Kerf bar and 20NK chain combos!



I sure didnt but im in need of a whole new setup. Been cutting alot of wood lately. Selling it to a BBQ restaurant says he needs all i can cut.

Edit: I dont think any of those narrow kerf chains will fit my echo.....


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## GTP (Oct 23, 2010)

ClayKann101 said:


> I sure didnt but im in need of a whole new setup. Been cutting alot of wood lately. Selling it to a BBQ restaurant says he needs all i can cut.
> 
> Edit: I dont think any of those narrow kerf chains will fit my echo.....



I am fairly certain this set up will fit our Echos.
http://www.baileysonline.com/itemdetail.asp?item=BCC 16 SJ50

Also this is a good set-up at a great price...
http://www.baileysonline.com/itemdetail.asp?item=BHC+16+EP50&catID=686

Hope this helps you feed the restaurant !!:chainsawguy:


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## mountainlake (Oct 23, 2010)

GTP said:


> I am fairly certain this set up will fit our Echos.
> http://www.baileysonline.com/itemdetail.asp?item=BCC 16 SJ50
> 
> Also this is a good set-up at a great price...
> ...



And if you buy 3 or more they'er $12.95 each. Steve


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## PLMCRZY (Oct 23, 2010)

GTP said:


> I am fairly certain this set up will fit our Echos.
> http://www.baileysonline.com/itemdetail.asp?item=BCC 16 SJ50
> 
> Also this is a good set-up at a great price...
> ...



Well i didnt see it in the list on the bottom of the page i figured it didnt work! I also see it says i need a .325 drive sprocket to run it, i dont think my echo has that. How much better is a NK chain compared to 3/8 lo pro which is what im running now.


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## fistpatrick (Oct 27, 2010)

I subscribed to arboristsite just to see the slides of this mod as well.
Great job. I am currently working on mine. I just bought my CS-400 about a month ago and already ran about 3 tanks of gas through it. I can't wait to get the mod done and see how it has improved. Do I need to adjust the carb too?
If I don't will it run to lean? I believe it is running rich from the factory right now till the rings are seated.


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## sjp (Oct 27, 2010)

the cat. in the muffler pic is real simlar to catalicit convertor yamaha was useing a while back many problems of the cat cloging and breaking down and peices geting suck in combustion chamber and doing real damage


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## mountainlake (Oct 27, 2010)

fistpatrick said:


> I subscribed to arboristsite just to see the slides of this mod as well.
> Great job. I am currently working on mine. I just bought my CS-400 about a month ago and already ran about 3 tanks of gas through it. I can't wait to get the mod done and see how it has improved. Do I need to adjust the carb too?
> If I don't will it run to lean? I believe it is running rich from the factory right now till the rings are seated.



Most are set way lean from the factory, the rev limiter will fool you into thinking it's set rich. These saws pick up a LOT with a good muff modd. Steve


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## fistpatrick (Oct 28, 2010)

Well I can do a clean job on the muffler mod thanks to these pictures, but I don't know much about the carb and rev limiters. After I finish the muffler should I take it to the saw shop and have them tune the carb and make sure it isn't running to lean?

Once I do the muffler mod is it required to remove the rev limiter?


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## fistpatrick (Nov 3, 2010)

*limiter caps*



ClayKann101 said:


> Take a drill and drill out the cat then flip it upside down and make sure all the little particles are out.
> 
> Limiter caps are easy, take a dry wall screw or something similar and thread them into the cap, now take some pliers or whatever and pry them out. Once removed you can tune your high speed needle and your low speed needle. I recommend richening it up a bit until about 3 or 4 tanks, then lean it out.



Can anyone show pictures or know a link to a post showing this procedure?
I did the muff mod and need to tune. It will be easier for me if someone who has removed the limiter caps could give me some help. Thanks

-- never mind I figured it out. It's pretty easy --


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## HLC03 (Nov 3, 2010)

*Chainsaw*

If you look in the original team fast slides it looks like the cat was cut/drilled out kind of sloppily. When I did my mod i used a 1/2" old drill bit and a can of wd-40 and drilled as much cat-crap as i could out, then I used my dremel with a couple different metal de-burring/sanding bits and drums. Then I washed it out and went to town polishing it (the inside of the muffler that i just removed the cat from). I got it to a mirror like finish in there. I figured it might flow better based on the way engine builders port and polish everything for better flow characteristics. I'm probably being anal, but in my mind it added ten horsepower, hahahha. I would love to have that flow bench, must be a great way to measure minute changes like this. Good luck with your modding to anyone whos been following this thread. Also, I painted my muffler with about 4-5 coats of Rustoleum 1200degree paint. This junk is GARBAGE. It started to melt after the first test run of the saw, and now after the 5th or 6th job using the saw it still melts and gets saw chips stuck in the paint. There is no way that little engine is putting out over 1200 degrees on the exhaust side. I should have just sprung for the 2000 degree VHT stuff.

Adam


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## BryanEx (Nov 3, 2010)

HLC03 said:


> Also, I painted my muffler with about 4-5 coats of Rustoleum 1200degree paint. This junk is GARBAGE.


Hmmm... I've had good luck with it on my wood-fired maple syrup evaporator which runs at about 900 degrees but it's also lined with fire brick. I wonder if "stove black" would be a better choice for mufflers. It likely depends on what the muffler is actually made from for which paint is best. Just out of curiosity, what temp does a muffler get anyway?


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## o8f150 (Nov 3, 2010)

BryanEx said:


> Hmmm... I've had good luck with it on my wood-fired maple syrup evaporator which runs at about 900 degrees but it's also lined with fire brick. I wonder if "stove black" would be a better choice for mufflers. It likely depends on what the muffler is actually made from for which paint is best. Just out of curiosity, what temp does a muffler get anyway?



i use the high temp engine paint from the parts store,,works good for me


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## RTK (Nov 3, 2010)

BryanEx said:


> Hmmm... I've had good luck with it on my wood-fired maple syrup evaporator which runs at about 900 degrees but it's also lined with fire brick. I wonder if "stove black" would be a better choice for mufflers. It likely depends on what the muffler is actually made from for which paint is best. Just out of curiosity, what temp does a muffler get anyway?



In a different 2 stroke racing application we hit around 900*F EGT with an on-board temp sensor running alcohol.


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## HLC03 (Nov 4, 2010)

@RTK : Doesn't alcohol race fuel burn cooler than regular 93octane pump gas?

Sounds like we need someone with an inferred thermometer to find out what a chainsaws exhaust gas temperature reaches. I thought that it couldn't be more than 7 or 8 hundred degrees. But the paint on my muffler basically heats up and starts to bubble a little and if you took a screwdriver to it you could scrape the paint to the bare metal. It seems to have cured a little since running a couple tanks of 93 through it but it still heats up to the point of melting paint and getting saw chips stuck in.

Adam:greenchainsaw:


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## RTK (Nov 4, 2010)

Alcohol runs a little cooler, but I doubt the muffler temp runs much over that ..........Never temp'd a muffler on a saw, done a few CHT's though. In our application we use EGT to tune our racing 2 strokes not CHT


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## mountainlake (Nov 4, 2010)

Exhaust temp on snowmobiles are around 1100, they start melting down when hitting 1200 to 1300. Steve


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## fistpatrick (Nov 4, 2010)

HLC03 said:


> @RTK : Doesn't alcohol race fuel burn cooler than regular 93octane pump gas?
> 
> Sounds like we need someone with an inferred thermometer to find out what a chainsaws exhaust gas temperature reaches. I thought that it couldn't be more than 7 or 8 hundred degrees. But the paint on my muffler basically heats up and starts to bubble a little and if you took a screwdriver to it you could scrape the paint to the bare metal. It seems to have cured a little since running a couple tanks of 93 through it but it still heats up to the point of melting paint and getting saw chips stuck in.
> 
> Adam:greenchainsaw:



Adam, you just put it on to thick, to many coats. I used the same paint on my CS-400 and it works great. I only did 2 very light coats. My buddy did a bunch of coats on his and has the same problem.


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## HLC03 (Nov 4, 2010)

fistpatrick said:


> Adam, you just put it on to thick, to many coats. I used the same paint on my CS-400 and it works great. I only did 2 very light coats. My buddy did a bunch of coats on his and has the same problem.



well no 5hit? I guess this is the answer I've been looking for. I guess i should strip the muffler and start over. It doesn't look too bad, and I'm the only one who will notice but you know how that goes. 

thanks for that man, i even started a egt thread and everything. i'm still a noob.


adam


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## BryanEx (Nov 5, 2010)

fistpatrick said:


> Adam, you just put it on to thick, to many coats. I used the same paint on my CS-400 and it works great. I only did 2 very light coats. My buddy did a bunch of coats on his and has the same problem.


Excellent fistpatrick. I that variable never even crossed my mind but now that you mention it, I have had that issue in other situations - usually when I've tried to "use up the rest of the can".


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## Deer Assassin (Jan 24, 2011)

looks like my new cs-400 is going to get modded for sure now


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## Deer Assassin (Jan 24, 2011)

seems like the flow data is better with the screen out and no deflector 


im going to go that route


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## PLMCRZY (Jan 24, 2011)

Deer Assassin said:


> looks like my new cs-400 is going to get modded for sure now


 
You will be happy, its a really nice running saw.


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## Team FAST (Jan 24, 2011)

Deer Assassin said:


> seems like the flow data is better with the screen out and no deflector
> 
> 
> im going to go that route



It is, but on an otherwise stock saw with a properly tuned carb, I don't think its nescessary. You still want a slight flow restriction in the muffler to maintain a little exhaust backpressure to assist with exhaust scavenging. Too much is not always the right answer.

-erik
(aka Team FAST)


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## Deer Assassin (Jan 24, 2011)

i see ur point

no screen but leave deflector


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## Team FAST (Jan 24, 2011)

HLC03 said:


> If you look in the original team fast slides it looks like the cat was cut/drilled out kind of sloppily.


 
Not really. The picture makes it look worse than it is. The ragged appearance is actually the exhaust gasket residue. Polishing the interior is not nescessary...diminisihing returns and no measureable flow difference. The cross sectional area is so large in that section as compared to the exhaust port that it won't have any significant impact on the flow. I cleaned out the center large bore with a sanding drun and a flap wheel.


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## Cliff R (Jan 25, 2011)

how the hell do i get to those baffle holes? do i need to split the muffler and braze it back together?

No, the holes can be opened up easily without splitting the muffler. Clamp it firmly in a shop vise with some leather or couple of show rags. Use a hand drill and open up the holes. It will grab when it goes thru, so make sure the muffer is clamped securely and you have a good hold on the drill. 

I reached in and cleaned up the holes with a long shank round carbide cutter on an air grinder.

I've modded two of those mufflers, takes about 20 minutes. I put the deflectors back on them, just opened them up some.

It's a big wake up call for those saws. My muffler modded CS-370 was faster than a stock CS-400 in timed cutting tests. 

I really like the CS-370/400's, but they are not in the same league as any of my 50-55cc saws, not even close.

They do have a LOT of "grunt" for such small saws, and great for limbing. I run 14" bars on both of mine, with 3/8" LP chains......Cliff


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## mountainlake (Jan 25, 2011)

My CS400 is in the same league as my 50cc home owner saws, cut faster than one and just a hair slower than the other. The CS400 has a lot more snort than my CS370. Steve


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## brokenbudget (Jan 29, 2011)

heres one i did last fall on one i gave to my friend al. i ended up totaly gutting everything out of it (i cut it open:doctor, made a couple of braces to fit between the 'halves' out of tubing and redid the deflector. i used 1/2" o.d. stainless tubing for the ports (about 3/4" long). silver solder works perfect.





the saw falt out rips compared to what it was with the cat in there, and it's as loud as a homey xl12.


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## HLC03 (Jul 10, 2011)

*Bump*

Hello Everyone!

Been a really long time since I've posted here, and I just re-read this thread and thought that it needed a bump to the top again for anyone who owns an Echo cs-370, or cs-400. Since the last time I posted I installed a baliey's Arbor Pro 16" bar (down from the stock thin radius 18" bar) and Bailey's Woodland Pro 16" chain. Wow, what a difference the more aggressive chain makes... I absolutely love this setup and I think I might buy a 14" b/c to play with as well. These Echo saws are unstoppable with the muffler-mod described in this thread and a little proper carb tuning goes a long way as well. Thanks very much to TeamFast, and all the others that have contributed. I think I am going to buy myself an Echo 600p as a new toy soon, the porting video that blsnelling did on youtube is pretty awesome for the 600p, looks very nasty! Anyone port the cs-400? Anyhow, lets keep this thread alive for anyone looking to buy/wake-up their CS-400, what a difference a little muffler mod and more aggressive b/c make on this little 40cc saw, great limber, great felling saw for smaller stuff, and great for hoisting up in the tree when you need something a little more powerful than your little tree saw, (like my CS-341). This is a powerhouse of a 40cc, absolutely awesome all around small saw.

Have a good rest of your weekend guys,
Adam
hlc03


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## mountainlake (Jul 10, 2011)

With a muff modd and tuning these saws really cut, 13# ready to cut on a good scale. Steve


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## motobike (Jul 10, 2011)

*Echo Muffler Mod*

I am looking forward to putting this mod into action on my saws.

Thank You


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## PLMCRZY (Jul 10, 2011)

Just modded my buds cs 400 i forgot how badass they sound when you mod the muffler. I have not put it in wood just yet. Im trying to talk him into giving me the saw, after i do a bb kit on a makita for him.


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## motobike (Jul 10, 2011)

*Restrictive Echo Mufflers*

I actually just found this thread, somehow missed it when it started.

I have been opening up the smaller Echos for several years; and oh my, what a difference. I have a few CS-346's, that had the about the same catlytic converter. Took them out of all the saws, worked on the deflector and removed the screen.

The CS-345 is the same saw, before catlytic converter; if you find one of them, use that muffler and do the deflector and screen work.

I have a new CS-530 but haven't even run it yet; but will apply the Team Fast procedure to it too. 

Also I am thinking about getting a new CS-500p. Has anybody worked on any of these yet. It is the Shindaiwa/Echo project.


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## wyk (Jul 16, 2011)

Zombiechopper said:


> the last slide where it says, "40cc Echo now hangs with 55cc saws!"
> 
> You haven't run too many 50cc saws have you? Let me just suggest you change that slide.


 
I can see it hanging with them, if not beating them. My MS250 has no trouble beating my buds 026 and 346xp. I've posted the vid several times.


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## mountainlake (Jul 17, 2011)

Zombiechopper said:


> the last slide where it says, "40cc Echo now hangs with 55cc saws!"
> 
> You haven't run too many 50cc saws have you? Let me just suggest you change that slide.


 
Kind of a old thread that I missed, Zombie should run a muff modded CS400 and then comment. I ran my CS400 against my Rancher 55 53c which the CS400 beat easy, against a good running 029 56cc that I sold (no reason to keep a 18# saws when a 13# saw will cut just as fast) it was just about dead even with the 029 winning by a hair. Steve


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## Jakeiscrazy (Sep 11, 2011)

Man this is temping....... On one hand I really want the extra power(insert Tim the Tool Man Grunt) but I'm a little nervous about voiding the warranty. Thought's on that issue?


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## mountainlake (Sep 11, 2011)

Yes, if you have it tuned right you'll never need the warrenty and if something did happen you could get a new or used unmodded muff. Steve


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## John in MA (Sep 11, 2011)

Is the CS-440 (the new one) muffler anything like this one?


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## Jakeiscrazy (Sep 11, 2011)

mountainlake said:


> Yes, if you have it tuned right you'll never need the warrenty and if something did happen you could get a new or used unmodded muff. Steve


 
True, I think I'll do it for the boost in power.


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## fische08 (Dec 21, 2011)

Just GREAT! just moved up from homeowner saws and used my cs-400 for 3/4 of a tank and now I have to mod the muff! I cut 4-5 cords of firewood last year and now every year in future and theres no way I'm gonna let that cat muff cause excess heat in my new baby's engine. Funny since I chose this over husky for warranty now it's gonna be gone!


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## Magnumfloyd (Jan 15, 2012)

Is one turn out a good starting point for the h carb neddle after doing a muffler mod.


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## mountainlake (Jan 16, 2012)

No 3-1/2 turns out on both the [email protected] on the newer Echo saws. Must have finer threads or a different tip than older saws. Steve


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## Magnumfloyd (Jan 16, 2012)

I meant one past the stock setting but I'll turn them in then back the 3 1/2 saw is new never ran.

Sent from my Nexus S 4G using Tapatalk


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## mountainlake (Jan 16, 2012)

Yes 1 turn out past stock should be rich make sure it really blubbers, then lean out till it cuts the best in bigger wood. I think most end up around 1/2 turn out from stock. Steve


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## Magnumfloyd (Jan 16, 2012)

Thanks for the info mountain lake this is one strong little saw modded never ran stock though. 3 1/2 was a little much on the l

Sent from my Nexus S 4G using Tapatalk


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## mountainlake (Jan 16, 2012)

When stock even with proper tuning they are just average, big increases with the muff modd. Steve


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## stubnail67 (Jan 16, 2012)

*like!!!*



mountainlake said:


> When stock even with proper tuning they are just average, big increases with the muff modd. Steve



think im going to get a used one and modd it soon what size bar ya all using the 18 or a 16?


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## Ironhand (Jan 17, 2012)

stubnail67 said:


> think im going to get a used one and modd it soon what size bar ya all using the 18 or a 16?



16" works well.


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## Magnumfloyd (Jan 23, 2012)

I'm very pleased with the 18" bar and have used all 18 +

Sent from my Nexus S 4G using Tapatalk


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## brokenbudget (Jan 23, 2012)

for balance and power, the 16" is best for this saw. run some 91vxl oregon chain and she'll cut very well


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## dboyd351 (Jan 30, 2012)

Subscribed


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## Magnumfloyd (Feb 8, 2012)

Did the muffler mod now I have a squeal.

Sent from my Nexus S 4G using Tapatalk


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## PLMCRZY (Feb 8, 2012)

Magnumfloyd said:


> Did the muffler mod now I have a squeal.
> 
> Sent from my Nexus S 4G using Tapatalk



A squeal????


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## Magnumfloyd (Feb 8, 2012)

Yeah at idle

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## fische08 (Feb 9, 2012)

related question, I've seen a few people mention that the screw caps help hold the screws from creaping, have any of you experienced this or know that it is false(I have a newer 2011 model)? I'm just trying to figure out how I will get the caps off and if I want to preserve their functional condition before I do this mod.


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## PLMCRZY (Feb 9, 2012)

Magnumfloyd said:


> Yeah at idle
> 
> Sent from my Nexus S 4G using Tapatalk



Ok why don't you either tell us where the squeal is coming from, if it stops when you give it gas or gets worse. 

None of us can read your mind and tell you what's wrong with it when all you say is "squeal at idle". We need a lot more info to help you. Your obviously doing something wrong since this is the 2nd saw you made "squeal"


Sent from my iPhone using Tapatalk


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## PLMCRZY (Feb 9, 2012)

fische08 said:


> related question, I've seen a few people mention that the screw caps help hold the screws from creaping, have any of you experienced this or know that it is false(I have a newer 2011 model)? I'm just trying to figure out how I will get the caps off and if I want to preserve their functional condition before I do this mod.



I popped mine off and threw them in the trash, they never moved on me. 


Sent from my iPhone using Tapatalk


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## Magnumfloyd (Feb 9, 2012)

squeals at idle goes away when the clutch locks up all I did was drill the cat out with a taper bit and cleaned all the shavings out and bolted back on and richened it up.

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## blkcloud (Feb 9, 2012)

I pulled the muffler off my cs4400 this evening.. all ready to rip the guts out.. to my surprise there was nothing in there.. from what I could tell it was pretty much a hollow can with a side pipe going into the screen and deflector, I took the screen and deflector off but didnt notice any difference.. Is there any way to mod this muffler? thanks!


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## rmotoman (Feb 9, 2012)

If the muffler is same as the 510/520 you have to cut the tube out of the muffler. It is to small and restricts flow.


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## PLMCRZY (Feb 10, 2012)

Magnumfloyd said:


> squeals at idle goes away when the clutch locks up all I did was drill the cat out with a taper bit and cleaned all the shavings out and bolted back on and richened it up.
> 
> Sent from my Nexus S 4G using Tapatalk



Do you let the saw sit outside in the rain? Now I can't remember but I believe there is bearing that the clutch rides on. Take some high temp grease and put a little on it. I had a older Poulan that made a squeal. 


Sent from my iPhone using Tapatalk


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## PLMCRZY (Feb 10, 2012)

blkcloud said:


> I pulled the muffler off my cs4400 this evening.. all ready to rip the guts out.. to my surprise there was nothing in there.. from what I could tell it was pretty much a hollow can with a side pipe going into the screen and deflector, I took the screen and deflector off but didnt notice any difference.. Is there any way to mod this muffler? thanks!



No there's not put it back together and cut wood. 


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## redunshee (Feb 10, 2012)

PLMCRZY said:


> No there's not put it back together and cut wood.
> 
> 
> Sent from my iPhone using Tapatalk



Whew! Purple type! Wakes one up that's for sure. LOL:msp_wink:


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## stubnail67 (Feb 10, 2012)

*400vs 2600?*

so i just got a poulan 2600 in nice light lil saw needs work but cylinder is great and it has spark.... i was curious to know if anyone had cut with both these saws with muffler mods???... on the 2600 will only have very lil mods to make loose the screen and open it up drill the baffle holes.... these saws are pretty close cc wise size and weight... the one i got is real clean im thinking of keepin her but ive been wanting an echo-400 with all i have read on this thread anyone have both???? how do they satck up if you cut with each one same bar and chain?


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## steve316 (Feb 10, 2012)

*cs400*

the cs 400 will be the easyest saw to start.the muff on the 2600 is very restrictive and should respond well to moding. the muff on the 295 pro is so restrictive you wonder how it runs,and the 2600 is close to the same.Steve


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## stubnail67 (Feb 11, 2012)

*huh?*



steve316 said:


> the cs 400 will be the easyest saw to start.the muff on the 2600 is very restrictive and should respond well to moding. the muff on the 295 pro is so restrictive you wonder how it runs,and the 2600 is close to the same.Steve



i think your wrong my brother! the 2600 was easy take apart muffler remove screen drill it put it back together and done in20 minutes or so... then was the tuning in wood that took me a lil bit to get the plug that nice brown .. but i was sorta playing... my 295 i agree its very restricted i may buy an older 2900 muff .... thats like the 2600 was it was cake.....i have to say my lil 2600 cut dam good with new bar and chain all tuned up in 10 inch pine.....better then my 295 i need to muffler mod it and drop down a bar size for sure!!!! i wish i was close to someone with and echo id like to race one they say those lil echos cant be beat i think i will get me a good used one and find out myself... i paid about 40 bucks for the 2600 perfect P/c and carb!!!


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## genestar (Apr 12, 2012)

*cs-400 muffler mod*

I just got my cs-400 yesterday. 
I think I will break it in first before I mod it?
Any thoughts on this?

Will be running 87 mixed at 28/1...klots super techni plate...same as every two stroke I own.


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## Ironhand (Apr 12, 2012)

genestar said:


> I just got my cs-400 yesterday.
> I think I will break it in first before I mod it?
> Any thoughts on this?
> 
> Will be running 87 mixed at 28/1...klots super techni plate...same as every two stroke I own.



I would suggest 4-5 tanks before you mod it. You won't believe the difference it makes. And just my $0.02, but 28:1 is heavy on the oil. 40 or 50:1 is fine.


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## mountainlake (Apr 12, 2012)

Pull the caps and tune before you run it, a lot come set burn up lean. 40 to 1 is good. Steve


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## genestar (Apr 12, 2012)

*tuned*



mountainlake said:


> Pull the caps and tune before you run it, a lot come set burn up lean. 40 to 1 is good. Steve



Thanks! 
I cut some small 5" logs into shorter logs and mostly gave it short blips before the cuts...then checked the plug. It was super lean.
Pulled the caps, broke one and pulled the metal plate off with the cap. Managed to save one. 
I wanted to save both and shave the tabs off and put them back on...oh well.
The fuel air mixture was waaaay to lean.


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## wvwoodcutter (Aug 14, 2012)

I just ordered a Echo CS-400 and expecting it to be lean also, Iam not sure where to start on adjusting the carb so that its spot on. Can someone point me in the right direction? Thank You


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## rmotoman (Aug 14, 2012)

Can you tell if a saw is running lean or rich? If you can than turn the high side out maybe 1 turn from the factory setting than make test cuts and slowly turn it in until the saw quits four stroking when cutting wood. I set mine plenty rich (four stroked through most of a cut) for the first 4 or 5 tankfuls. I haven't touched the low side it was set very close from the factory.


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## borat (Oct 18, 2012)

*Did the muffler on my CS346 today*

After reading this thread and looking at the pictures posted, i decided to go to work on my Echo CS346. 

First thing I noticed was that the muffler is different. I modified the exhaust outlet to match the size of the exhaust port on the engine. There was no need to modify the deflector because it was already wide open. Once I opened up the exhaust outlet, I could see a horizontal baffle between the intake and outlet sides of the muffler. I thought of trying to bend it a bit to open the space at the bottom but it wouldn't budge. Accordingly, I got out the Dremmel and bored a 3/8" hole in the centre of the baffle that lines up directly center with the exhaust outlet. I put blue locktite on the screws, buttoned everything back up and took it for a few test cuts. 

Seat-of-the-pants dyno indicates an immediate improvement in how quickly the engine revs up and seems to sustain more power while under substantial load. In the past, the saw would cut fairly well on eight or ten inch diameter sticks, but on big wood, the saw would seem to bite off more than it could chew and power would sag. Now it seems considerably more eager to go through larger logs. I think the carb is set a bit rich. It popcorns at wide open throttle and I figure I can lean it out a tad to squeeze a bit more power out of it. I'm pretty familiar with tuning two cycle carbs (I own a number of vintage Yamaha 2 cycle motorcycles and tons of two stroke ***) so I know the importance of not setting the carb too lean. 

Overall, I'm pretty much impressed with this little saw. Since owning it, I hardly use my Jonsereds 630 and 670. I've got to have a lot of big sticks to buck to pull one of those saws out.


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## 1fretless (Oct 18, 2012)

*Another warantee voided!*

Hey folks

Completed these mods over the week and wanted to also thank team fast for this guide.
The CS-400 is a fine saw straight from the factory so consider carefully your options for 
service in the future before heading down the "crossroads". 

I burned around a gallon of fuel prior to performing the modifications. 

The result is a easier breathing saw that has H/L adjustability. 

Runs better for certain and allowed me to fine tune her perfectly. 

A few notes from my experience:

The catylitic converter is exactly that so expect a platinum and ceramic 
honeycomb requiring brute force to remove. A standard screwdriver and hammer!
or drill it out. I used a small drum sander to clean up the inner sleeve of material 
remnants once the guts were removed. 

The saw is no louder at all. If anything it's less frenetic!

Please note team fast mentions the need for some level of back pressure for scavenge!

Not much on removing the H/L limit sleeves....

I followed the idea of using a long drywall screw. Chopped off the very tip and slowly
screwed into the sleeves which pulled out the metal retaining ring and limiters as a whole
assembly. Concerned enough to retain their use to keep the screws from moving during
use I nipped off the "wings" and reinstalled the sleeves and retainer. ROCKS!

Tuned her up this evening great link to the video with setting the high and 4/stroking
in the load of a cut. I kept a little burble just to break her in over a few more tanks
but she cuts really well.

Just another big thank-you to everyone who posted and offered their solutions. 

I had a spare part lodged under my carb - a wire grommet !
guess it was lost during assembly. If the builder hits the sweet spot on the
H/L the limiters might be workable I'm at a full turn out on the H almost there....

My grouse with this saw is the oiler is messy and took awhile to get it right
but it runs thru the bar oil - sure miss the thumb pump for the bar oil. 

The top handle is too narrow at the safety for me needs just a little bending!

Safety clutch is hi impact plastic but seems cheap and fragile but the clutch
Really works very well.

You sure can't beat the ease of chain changes with the adjuster the fiddley part
but just the bar bolts and swap. Very sweet....

So far starts easy and is an easy puller. 

Get a descent Oregon chain and the foliage trembles!

Thanks a ton folks

Most of all be CAREFUL folks use yer head and think safey!


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## Philbert (Oct 31, 2012)

*Service Manual fo CS-400?*

Any chance one of you Echo Enthusiasts has a *Service Manual* for this saw that they could share? I tried the "_Beg for Manuals_" thread but got no bites.

I recently picked up a CS-400 and like to have the SM for each saw, especially for reference a few years down the line when i am more likely to need it. Figured that one of you guys might have snagged a copy along the way.

Thanks a bunch.

Philbert


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## dboyd351 (Oct 31, 2012)

Philbert, I didn't find the actual service manual, but these should help, from the Echo site: 

Operator's manual
http://www.echo-usa.com/getattachment/07628055-6ed6-492b-9057-0bce6550dbed

Parts catalog
http://www.echo-usa.com/getattachment/e8875cdb-8896-4df4-ad14-7cd3cef6ebe8

Link to more parts catalogs for the cs-400
Chainsaws, Trimmers, Blowers, Edgers and Outdoor Power Equipment | ECHO USA

CS-400 video library
ECHO Product Feature Videos | ECHO USA


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## thehallfamily1 (Nov 21, 2012)

*muffler mod comple and tuned = bad a$$*

when i first got my cs 400 out the box it would take 3 minutes to warm up and finally get running, it would bog down through cuts and was just a plain pathetic saw, my 1995 beat to crap craftsman would out preform the new echo????? i found this troubling and came online to find answers i then found this site and did the mods and tuning and dang you guuys arent joking its a whole new animal, thank you guys for the helpful thread and rejuvenating the epa restricted saw to its youth lol, im very happy how things turned out !!!!!


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## rmotoman (Nov 21, 2012)

Welcome to AS. It is amazing how much better a 400 runs when the muffler is opened up and carb adjusted.


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## BeansBaxter (Nov 21, 2012)

I got mine about 4 years ago and it was a decent runner but felt underpowered. I didn't want to void my warranty so I lived with it.

I finally took the plunge last week and drilled out the cat and pulled the limiter caps. Man, oh man what a difference that makes!

Now I just need to throw decent loop of chain on there instead of that crappy 91VG it came with. Why did I wait so long?


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## Michael II (Oct 26, 2014)

I am unable to see the slides can anyone send them to me thanks


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## zogger (Oct 26, 2014)

BeansBaxter said:


> I got mine about 4 years ago and it was a decent runner but felt underpowered. I didn't want to void my warranty so I lived with it.
> 
> I finally took the plunge last week and drilled out the cat and pulled the limiter caps. Man, oh man what a difference that makes!
> 
> Now I just need to throw decent loop of chain on there instead of that crappy 91VG it came with. Why did I wait so long?



Just on general principles, I would think stock, run around ten tanks, if it hasn't broken and need warranty repairs by then, mod it. Ten tanks on a new saw should be enough to seat the rings and give ya an idea on how it runs.

Now I would make sure the H is as far rich as possible with the limiters first.


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## RedFir Down (Oct 26, 2014)

Michael II said:


> I am unable to see the slides can anyone send them to me thanks


I used a 3/4" hole saw to eliminate the cat. Be sure to clean up any remaining CAT material after you drill it out. (Go slow at first, the bit will try to walk around a little)




Next open the outlet on the muffler.




Then trim the deflector. I cut out the "flat" portion on the left side and cut the rounded part back a little too.




Also make sure you rinse out all the shavings and filings before you reinstall the muffler. (Degreaser and hot water works well for me)


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## Philbert (Oct 26, 2014)

Thanks for the pics. 

Philbert


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## handsplit! (Jul 19, 2015)

Team FAST said:


> I modified the muffler on my Echo CS-400 Chainsaw, mostly based on recent recommendations provided by many individuals posting in other threads on this forum.
> 
> However, I thought it might be interesting to quantify the airflow differences of the mods using a Superflow SF-110 flowbench. You can see how the various pieces of the muffler contribute to the airflow results, as well as a direct before/after comparison. The attachments tell the story.
> 
> ...



I would! Thanks


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## rmotoman (Jul 20, 2015)

handsplit! said:


> I would! Thanks


Since this thread is 5 years old I'm not sure team fast is still around. There sure were some great pics and info lost. 

The cs400 responds very well to pulling the caps and a muffler mod.


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## genestar (Jul 20, 2015)

I still run mine.
Used it this weekend for light pruning work.
I used it last Oct. on my elk hunt to cut up enough aspen for 11 nights worth of bonfires.
Iron wood, mesquite, salt cedar.....it does it all without complaints. 
I have two larger saws that have their strong points, but the CS400 is still super easy to start and light weight. 
If it died on the next job, I'd buy another one.

Sent from my SCH-I535 using Tapatalk


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## Brushpile (Jul 21, 2015)

I reckon the old CS400 is a pretty decent saw.
The trunk was fell by the power company. They left the rest for me to play with.
30+". Wasn't sure how it would do. Did just fine.


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## handsplit! (Jul 22, 2015)

Brushpile said:


> I reckon the old CS400 is a pretty decent saw.
> The trunk was fell by the power company. They left the rest for me to play with.
> 30+". Wasn't sure how it would do. Did just fine.
> View attachment 437092
> View attachment 437093



Im really happy with the CS-400. Wanting a bit more tho. Really like the CS-590!! Just cut into some 32" diameter popular. No problem! Next theres a 30" oak and 55' long shagbark hickory im workimg on. Ill try and post some photos.


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## Team FAST (Jul 23, 2015)

I am still around!

I will attach images of my slides from 2010. Enjoy!

Slide 1


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## Team FAST (Jul 23, 2015)

Slide 2


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## Team FAST (Jul 23, 2015)

Slide 3


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## Team FAST (Jul 23, 2015)

Slide 4


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## Team FAST (Jul 23, 2015)

Slide 5


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## Team FAST (Jul 23, 2015)

Slide 6


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## Team FAST (Jul 23, 2015)

Slide 7


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## Team FAST (Jul 23, 2015)

Slide 8


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## Team FAST (Jul 23, 2015)

Slide 9


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## Team FAST (Jul 23, 2015)

Slide 10


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## Team FAST (Jul 23, 2015)

And finally, Slide 11

Looking back at this, it's really not rocket science. I just wanted to provide some flow data to provide a little science to back up the "art" of muffler modding. The flow numbers align well with the actual performance improvements of the saw. Many folks have done this type mod over the years and provided me with similar feedback. 

Glad everyone still finds this useful!


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## Ira Mcclurkin (Nov 9, 2015)

Hi, I'm new to this forum and find it very interesting. Are there any recommendations for modifying the Echo cs680 chainsaw?


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## Chad Harding (Jun 16, 2016)

Team FAST said:


> *Echo CS-400 Muffler Mods*
> 
> Here's the last slide!


Yeah I just opened up the back and frorestricter to the next one w myderemil and left the wire mess alone. It made all the difference in the world. Prob took under half inch


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## Vail Ave (Sep 19, 2016)

I know this thread has been around for a long time. I recently modded my muffler and tuned my saw. It is an absolute amazing performer, and outperformed a couple other much bigger saws this last weekend. With the 18" bar completely buried in a 26" diameter ponderosa pine, it did not bog or flinch and really cut like butter. I did separate my muffler to remove the restriction. I also opened up 4 of the 6 internal baffle holes from roughly 1/4" to 5/16" - nothing too crazy. I also opened the outlet and deflector like most do. I did insert my spark arrestor screen and also carry a spare in my chainsaw box. I do a lot of cutting on BLM land for campouts so the spark arrestor must be installed. It runs great. To split the muffler I just ran it around my 1" belt sander to remove the lap seam. To re-assemble, I fusion welded it with my torch using .021" silican bronze filler and a 0 torch tip. I love acetalyne welding, so this was not an issue for me. You could TIG it as well. I ran my welds pretty cold to make sure I did not blow through. For this reason, I did not have the "stack of dimes" effect I normally like, but it worked great. If I did it again, I would split the muffler again. It really helps you see everything and clean everything out completely which took some time. If there is a little piece of metal still floating around in the muffler, the exhaust port and cylinder are only an inch away. Great thread, keep it up. I was thinking about adding a CS-590 to my fleet even though I do not really cut enough wood to justify it. But now, it is really hard to justify because this little 400 does so good, and it is so light and easy to handle, even for hours.


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## Philbert (Sep 19, 2016)

Vail Ave said:


> I love acetalyne welding, so this was not an issue for me.


Welcome to A.S.! Not everyone can weld, or can weld sheet metal, or has a torch - you could make friends here on the site really quickly by offering to weld up mufflers that others have split open, and mailing them back!

Philbert


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## Team FAST (Sep 19, 2016)

Nice job. welcome


Post some pics of your handiwork.
I have a CS-590 muffler mod thread you may be interested in.


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## Cliff R (Sep 20, 2016)

"Great thread, keep it up. I was thinking about adding a CS-590 to my fleet even though I do not really cut enough wood to justify it."

The CS-590 is not even in the same league as the CS-400, so there is really no comparison between them anyplace, especially in the power output department. The CS-590 is basically a 60cc Pro saw with a laminated bar on it. I've been running the bag off of mine, it's stock other than a minor mod to the muffler deflector and removing the limiter caps and giving it some fuel. Spent the last few days cross-cutting some HUGE pieces of Ash to make them more manageable to get to the splitter. It noodles about as fast as it cuts in the normal fashion, and never even thinks about clogging up. I use the shavings for the nesting boxes in my chicken coup, and the rest around the house in the flower beds......Cliff


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## Vail Ave (Sep 20, 2016)

I decided to do the muffler mod kind of last minute before a trip up north (both in direction and 6500 feet higher in elevation) to cut wood. I was in a bit of a rush to ensure I got it done in one night, so regrettably, I failed to take any photos of the internal muffler baffle, or any of the project at all. I will remove the muffler and show pictures of the outside. I will be quite embarrassed for anyone to see the welds. They are solid from functional standpoint, but again, I did not have a spare muffler, so blowing through not knowing the quality of the muffler can was my biggest concern. As mentioned, I ran things quite cold, which does not contribute to having the welds look nice. Not to get off topic, but on the subject of acetylene welding, which is an ideal method to re-join the two halves of this little muffler - a lot of folks that have the gear to live the rustic and strenuous life, have what we are talking about here - saws and an oxy-acetylene torch. Of all the friends I know that weld, most do not consider their oxy-acetylene torch rig to be a welding device. They consider it a cutting and heating device, and they only have the cutting torch head on it. Most have long since forgotten that their torch came with welding head and multiple tips. I totally get that - if I am in a hurry, I grab the mig. Done. But for many years, I practiced with my torch constantly and used it to weld anytime I could instead of more modern methods. I mention this because if you have a farm, ranch or shop and do have an oxy-acetylene rig - a.k.a - "gas-axe", "Tennessee speed wrench" or an "Arkansas Ratchet", re-acquaint yourself with the welding side of your torch system. It is an awesome resource. Most of the planes in WWI were built using torch welding. So, with a little practice, things like chainsaw mufflers are easy. I am way, way out of practice now. I have not done a lot of welding of any kind in about 10 years just due to lifestyle changes (married, kids, moved cross-country, etc), but it still only took me 10 minutes to weld this muffler, so those years of practice are still in my hands somewhere. haha. 

I am pretty a pretty busy guy, but I am happy to help anyone I can get their muffler back together. If you live in an area where there is a shop that does welding that could gas or tig weld this little guy back together for you, they would probably charge you less than the cost of shipping this thing both ways. But if you have no other resource, I can weld it back together for you. What would be more interesting is to do a little video on it so that those who have interest in it can practice a little and then do it themselves if they do have a torch. 

Since I don't have any pics of welding the muffler, here are a couple of me making a rear fender for my chopper. This was many years ago, but when it comes to gas welding, nothing has changed.


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## Vail Ave (Sep 21, 2016)

Here are pics of the welded muffler.


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## EchoCS400 (Jun 17, 2017)

New to the forum here... I've used the old mans Jonsered growing up and have borrowed the father-in-laws Poulan but figured it was time to buy my own saw.

I just picked up a New Echo CS400, partially for the warranty and reviews... but from what I've read I should really consider doing the MM, tune it and forget the warranty.

I've used the saw a handful of times, starts and idles fine but seems to be leaving a little on the table if you bury it in the wood. 
The reputable shop I purchased from said they "set it up", I haven't looked but i'm assuming that means they just turned the High all the way out that the screws allow.

Couple questions about the MM, is it really necessary to completely core the CAT? I've seen pics of guys just running a 1/2" bit on an angle towards the exhaust port with great results. I know some back pressure is always required and its easier to take more later than put back... and wide open doesn't always mean the most power.

In regards to tuning, I've got small engine experience from my dirtbike days so I'm sure I can handle it. Have any of you used a tach to setup the idle or Low adjustment? Or just setting the Low between lean and rich stumble?

From my understanding the Echo has a rev limiter so setting max RPM on the High with a tach isn't advisable.
Best to "tune it in the wood" for the High? Does the bury in the wood, then pull up to hear burble method work effective? 

Any tips or recommendations would be appreciated, especially pics!

Thanks!


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## Deleted member 149229 (Jun 17, 2017)

EchoCS400 said:


> I just picked up a New Echo CS400, partially for the warranty and reviews... but from what I've read I should really consider doing the MM, tune it and forget the warranty



The warranty is a joke. Lots of great threads on here how to tune and mm. You wont believe it's the same saw after you set it up.


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## EchoCS400 (Jun 18, 2017)

Dahmer said:


> The warranty is a joke. Lots of great threads on here how to tune and mm. You wont believe it's the same saw after you set it up.



Looked at the saw when I got home... I was right. "Dealer tuned" just meant they backed the H and L screw out as far as the tabs would allow.

I think I've convinced myself to go ahead with the MM and tune. I've read way to many good reviews to not do it. I don't think I've read anything bad about the CS400's yet. 

I'll continue my research on tuning, thanks!


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## AnthemBassMan (Jun 18, 2017)

EchoCS400 said:


> Looked at the saw when I got home... I was right. "Dealer tuned" just meant they backed the H and L screw out as far as the tabs would allow.
> 
> I think I've convinced myself to go ahead with the MM and tune. I've read way to many good reviews to not do it. I don't think I've read anything bad about the CS400's yet.
> 
> I'll continue my research on tuning, thanks!



I have your saw's slightly younger brother, the CS-370. I've already pulled the limiter caps from the carb screws and readjusted them. But I still have to drill through the cat to open up the breathing more. I'll probably just run a 1/2" bit through the cat towards the outlet instead of gutting the entire muffler. I've seen comments where it was done both ways with great results. And I'll be readjusting the screws once the MM has been done. 

L8R,
Matt


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## EchoCS400 (Jun 18, 2017)

AnthemBassMan said:


> I have your saw's slightly younger brother, the CS-370. I've already pulled the limiter caps from the carb screws and readjusted them. But I still have to drill through the cat to open up the breathing more. I'll probably just run a 1/2" bit through the cat towards the outlet instead of gutting the entire muffler. I've seen comments where it was done both ways with great results. And I'll be readjusting the screws once the MM has been done.
> 
> L8R,
> Matt



Keep me posted with your results. I'm new to the saw world, but feel this is a necessary mod for these saws.


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## AnthemBassMan (Jun 18, 2017)

EchoCS400 said:


> Keep me posted with your results. I'm new to the saw world, but feel this is a necessary mod for these saws.



Will do. From everything that I've read, it only helps wakes up this series of saw. Haven't read a single thing where it worsens the performance. 

L8R,
Matt


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## Deleted member 149229 (Jun 18, 2017)

I removed muffler and with a Dremel removed restricter plate on muffler, drilled hole thru cat towards exhaust port (ther's a plate in there). Then removed exhaust cover and again with a Dremel made the exhaust one hole by removing slats. Then tune. Not the same saw.


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## EchoCS400 (Jul 3, 2017)

Had the saw out this weekend and knocked down half a dozen trees for campsite firewood. Most of it was 6"-8" Poplar... and some larger deadfall.

Haven't had an issue running it in stock form as of yet, doesn't bog out but I'm curious to see how well it will run once I do the muffler mod. 
I'm not one to leave anything alone, and can't handle "leaving performance on the table".

Will report back once I get time to do the gut the muffler and tune!


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## Team FAST (Jul 10, 2017)

Vail Ave said:


> Here are pics of the welded muffler. View attachment 526869
> View attachment 526870
> View attachment 526871
> View attachment 526872
> View attachment 526873



Welds look good. To match the flow numbers I got from the testing, you should enlarge the opening to the outer exhaust deflector to be rectangular.


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## Gardy (Mar 7, 2018)

So I have the tools/ability to modify the deflector outlet, but not the internal baffle. Would doing just the deflector mod be any help? Thanks in advance!


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## Deleted member 149229 (Mar 7, 2018)

Gardy said:


> So I have the tools/ability to modify the deflector outlet, but not the internal baffle. Would doing just the deflector mod be any help? Thanks in advance!


Just drill holes thru it.


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## pdqdl (Dec 18, 2022)

This is an old thread, but apparently there is still some interest in reading it. All the original pictures seem to have been lost.

If anyone still has the original pictures, it would be great if you could add them to a new post in this thread. Thanks!


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## ATpro (Dec 18, 2022)

You can drill the cat out with a 7/8 hole saw, use a sheet rock screw to pull limiter caps on the carb. You may pull the plate off where the limiter caps are but if you do just push it back in and it will stay. Grind off the raised tabs on the limiter caps and put back on the carb adjuster screws, this will help keep the carb adjuster screws from moving from vibration but you can still fully adjust the carb.


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## Cliff R (Dec 19, 2022)

These are all I could find....


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