Reading a degree wheel (pics)

[Terry Syd]

The 'trough' I cut was just for testing purposes. I first went with the shaped crown and the stock 12 degrees of blowdown. Then to 14 degrees of blowdown and then to 16 degrees, both with the shaped crown. I found that with the 13,000 rev limiter that the 16 degrees and shaped crown was pushing the revs up too high. I then cut the jug for 14 degrees, but left the crown flat. That was close, but it needed the shaped crown to get it where I wanted it.

With the rakers set properly and a sharp chain, the rev limiter is no problem. However, if the chain gets dull the limiter will let me know it is time to swap out the chain.

I've done lots of other mods to the engine to get it where I wanted it; widen the exhaust port to 63% of bore, increased transfer area by 12.5%, ported the strato cutaway, increased intake timing (to the stock strato timing of 154 degrees), muffler mod of 150%+ of port area, a 570/575 carb, stuffed crankpin, higher flow air filter - so the exhaust timing is just part of the whole package.

These strato engines are a hoot. They have a tremendous amount of time/area for the intake cycle. They aren't as good as a rotary engine, but with that much area (intake port and transfer port area combined for intake) they can really breath if you allow them to. That is why I have the 570 carb on it. Since the intake timing is 'stock' (154 degrees for the strato port), it still has a very broad powerband.

Edit: The engine runs like it is a 60-65cc engine. I'm waiting for a re-match against my mate's 365. He narrowly beat me in 22" hardwood last year, but after some of the more recent mods I made, I think he is toast. - (and the powerhead weighs 10.8lbs)

 

[trappermike]

Whew,what a relief! You're not crazy after all,I couldn't understand you in the beginning...:msp_biggrinI'm joking) OK,I'll admit that I am...:redface:
Yes,one of the main reasons for using the "Trough" method was because you could experiment somewhat with ex. and trans. port timing without butchering the cylinder ports,you can replace the piston cheaper and easier(If the mods don't work well) and save the cylinder if you're experimenting.
Actually I'm fond of using the trough method to experiment on changing transfer port timing,they are not so easy to grind,and sometimes the mods don't work,it's hard to predict what transfer timing mods will actually do,but cylinder isn't ruined.:msp_smile:
I've never seen this motor so I can't really imagine how it's designed,it's interesting if not quirky.
Sounds like you did some serious mods to the little guy,you should slaughter your friend's saw in the next match.

 

[Terry Syd]

Yeah Mike, when I was racing bikes I never threw away an old piston. I would keep them and butcher them to try different timing figures or configurations (ie: staggered transfer openings). For some reason it is not an idea that has caught on with the chainsaw crowd, you don't read of anyone that is doing it.

You never know when you'll go too far with timing - until you go too far. With the piston trick you can find the sweet spot and then continue cutting the piston to confirm it was the sweet spot - then port the jug to the desired timing and put in a fresh piston.

 

[trappermike]

Terry you are exactly right. It's really an old-timer's trick,I've never seen anyone else use it in over 30 years,but it's a brilliant trick for exactly the reason you just gave.I gotta hunch you did a lot of mods on 2-stroke motorcycles... I learned as a motorcycle speed-tuning tool in my young days,back when 2-stroke bikes were king of the street,I rode a 500 Kawasaki triple for 13 years and could adsolutely waste any size bike on the street with it's fearsome acceleration,but as you probably know,the 500 had diabolical handling and absolutely no brakes,people who rode them and lived to tell about it are almost non-existant. I suffer a lot nowadays from arthritus in the many injuries I inflicted upon myself riding the thing,I'm probably only here because I got married and had to sell it. I could hear Heaven calling my name a few times on that thing,some truly scary moments that I would never want to re-live...:msp_scared:
You have to put your knowhow into something bigger and more conventional I think,like an 084 Stihl,I'd like to see the results of that! I can tell you could build something truly maniacal out of one.

 

[trappermike]

That's why I had a hard time understanding what you're saying before,your Auzzie slang kinda threw me off,sorry.

 

[Terry Syd]

"It's really an old-timer's trick" - Crikey, you pegged me, I've been working on engines since 1964.

 

[trappermike]

Wow...and I thought I was old.....:msp_mellow:

 

[Terry Syd]

Gee, thanks for the back-handed complement - I'll return it as soon as I find an opening to deliver one.

 

[trappermike]

Sorry but I'll bet I wasn't the only one confused by Australian terminology,I mean I'm a bit of a dunce sometimes. Here in North America we are on the "Upper" side of the planet(Northern Hemisphere),so we're not always hip about what's going on on the lower side of the planet(Southern Hemisphere), Up is North right?,so that's why you guys are called "Down Under"? You better my experience by ten years at least,I was just a kid in the 60's and missed the best cars and bikes.:msp_sad:
Did you play with old saws back then or were just playing with bikes way back,I'm wondering if you're familiar with the older saws,like the Stihl Lightning...I recently sold one,I've got an even older 275 Canadien chainsaw,125cc,but I doubt those old things were exported.I'm hanging onto that one for restoration and a Hotsaw build- an antique hotsaw. It has a few special weapons though like a removable head and 6 transfer ports,I'm looking forward to what I can get out of it.

Anyway I think I've strayed way off topic and better stop.
Good luck with the 'Usky mate.

 

[046]

what a clever idea to cut piston first to try out timing. transferring final timing settings to jug.

thanks for sharing...

Yeah Mike, when I was racing bikes I never threw away an old piston. I would keep them and butcher them to try different timing figures or configurations (ie: staggered transfer openings). For some reason it is not an idea that has caught on with the chainsaw crowd, you don't read of anyone that is doing it.

You never know when you'll go too far with timing - until you go too far. With the piston trick you can find the sweet spot and then continue cutting the piston to confirm it was the sweet spot - then port the jug to the desired timing and put in a fresh piston.

 

[parrisw]

Sorry but I'll bet I wasn't the only one confused by Australian terminology,I mean I'm a bit of a dunce sometimes. Here in North America we are on the "Upper" side of the planet(Northern Hemisphere),so we're not always hip about what's going on on the lower side of the planet(Southern Hemisphere), Up is North right?,so that's why you guys are called "Down Under"? You better my experience by ten years at least,I was just a kid in the 60's and missed the best cars and bikes.:msp_sad:
Did you play with old saws back then or were just playing with bikes way back,I'm wondering if you're familiar with the older saws,like the Stihl Lightning...I recently sold one,I've got an even older 275 Canadien chainsaw,125cc,but I doubt those old things were exported.I'm hanging onto that one for restoration and a Hotsaw build- an antique hotsaw. It has a few special weapons though like a removable head and 6 transfer ports,I'm looking forward to what I can get out of it.

Anyway I think I've strayed way off topic and better stop.
Good luck with the 'Usky mate.

Those 275's are quite rare. Would be shame to cut it up. I have a 270 dissembled.

Where in BC are you? I'm down in Victoria.

 

[RiverRat2]

what a clever idea to cut piston first to try out timing. transferring final timing settings to jug.

thanks for sharing...

it is a good Idea,,,, but I'm bettin ,,,, he didnt think of it,,,,,, some body clued him in,,,:wink2:

Them Aussie's
are smart,,,,, just not that smart!!!!! LOLOL!!!:msp_biggrin::msp_biggrin:

 

[trappermike]

I'm only a few miles away from you in Duncan. I saw the old Canadien here in a pawn shop about 10 years ago,I knew what it was and got it for $29. I took it home planning to restore it like new,then I saw the whole muffler was missing,kinda' shot up that plan. But seeing that it had a removable head,six transfer ports,and borable cast sleeve I decided to make an antique Hotsaw out of it,since it would be a dream to modify,125cc,and I've got some big race carbs,and perfect race pipe blueprints and templates for it too. Only problem the piston is fried,I talked to Wiseco and they may be able to make one for it. When I was in Victoria about 20 years ago I went to a little machine shop to have my billet alum. 090 head re-machined a bit,an older guy there said he was involved with the Canadien factory in Vancouver when it was going,and he still had some new pistons for the big old Canadiens(Of course I never knew I would need one then),I'm afraid he's probably gone now though...
They have a little Forest Exibition here most years and sometimes feature the odd saws,so I want to challenge the local Stihl and Husky dealers to a match against their 088's,3120's,and blow them outta the water with the ancient Canadien:hmm3grin2orange:, I don't think it would be hard at all...
Let me know what you're doing,or if you got an idea where to get a new piston. The cast sleeve in the cyl. is pretty thick,I calculated I could bore to almost 140+ cc's.

 

[parrisw]

I'm only a few miles away from you in Duncan. I saw the old Canadien here in a pawn shop about 10 years ago,I knew what it was and got it for $29. I took it home planning to restore it like new,then I saw the whole muffler was missing,kinda' shot up that plan. But seeing that it had a removable head,six transfer ports,and borable cast sleeve I decided to make an antique Hotsaw out of it,since it would be a dream to modify,125cc,and I've got some big race carbs,and perfect race pipe blueprints and templates for it too. Only problem the piston is fried,I talked to Wiseco and they may be able to make one for it. When I was in Victoria about 20 years ago I went to a little machine shop to have my billet alum. 090 head re-machined a bit,an older guy there said he was involved with the Canadien factory in Vancouver when it was going,and he still had some new pistons for the big old Canadiens(Of course I never knew I would need one then),I'm afraid he's probably gone now though...
They have a little Forest Exibition here most years and sometimes feature the odd saws,so I want to challenge the local Stihl and Husky dealers to a match against their 088's,3120's,and blow them outta the water with the ancient Canadien:hmm3grin2orange:, I don't think it would be hard at all...
Let me know what you're doing,or if you got an idea where to get a new piston. The cast sleeve in the cyl. is pretty thick,I calculated I could bore to almost 140+ cc's.

That sounds pretty cool. Do you remember the name of the machine shop or the person you dealt with? 275 parts are not easy to come by. I'm guessing you could retrofit a piston from a dirtbike motor or something. PM JacobJ on here he would know more then me. He's got a couple 275's, one I sent him.

 

[Terry Syd]

Yeah Rat, I ain't that smart. Guys were already doing it when I started doing it. In fact, if you look at an old copy of Gordon Jennings book on Two-Stroke Tuning you will see where he mentioned the mod and gave an illustration of how to do it.

 

[trappermike]

I can sort of remember how to get to the machine shop,but never knew the name or remember the street address unfortunately.

I learned the piston notch trick from an expert in 1975 who used to work for Suzuki in building and designing their competition engines for road racing and motocross,for a week straight he taught our class on 2-stroke speed tuning, even a few tricks I never heard of since. Also that method was published in a few speed tuning books,and Yamaha used to have a really good book on racing 2-strokes and data of their own,all their factory racing secrets,sure wished I had a copy of that... I think it may have been called Yamaha Speed Secrets,something like that,written around 1973...I use their specs to port an RD350 steet bike to the TR3 road racer specs,wow what a difference,no experimenting, the full data was there.
Sadly 2-stoke bikes are almost extinct now so most of that kind of info and data is long gone. I was horrified to see recently a lot of the newer MX bikes are 4-strokes-gag!!:msp_angry:

Maybe one day I could meet up with you in Victoria and we could see if the shop is still there and the guy is still around... As for a new piston,the old one is a full skirt design unlike modern motors,but I think Wiseco can modify a 4-stroke blank,before the ring grooves are cut,then they can cut me 2 grooves for pinned rings,not the 3 4-stroke ring grooves. To just go and make a new design piston is too much $$$(15 pistons min.),but they said they could probably make one for me from the blank of an existing similar piston. Anyway,no time or money for it now,it's a project for later,I have everything else to build it though. Of course the old Canadien will never be capable of competing in proffessional Loggers Sports(The crank and rod design are too weak I fear for real high revs) but it will be ok and fun to see in small local events.:msp_smile:

By the way,many years ago there was an old guy in this town who I knew and he had the biggest collection of running antique chainsaws I ever saw or heard of. He used to bring the odd one to the shop to show us. One day he brought a big Mercury twin cylinder 2-man saw and ran it,wow what a crazy looking thing,,twin fishtail mufflers,big bicycle handlebars, etc.,cool. Anyway he's passed away now,but I sometimes wonder where all his saws went... :bang:

 

[parrisw]

I can sort of remember how to get to the machine shop,but never knew the name or remember the street address unfortunately.

I learned the piston notch trick from an expert in 1975 who used to work for Suzuki in building and designing their competition engines for road racing and motocross,for a week straight he taught our class on 2-stroke speed tuning, even a few tricks I never heard of since. Also that method was published in a few speed tuning books,and Yamaha used to have a really good book on racing 2-strokes and data of their own,all their factory racing secrets,sure wished I had a copy of that... I think it may have been called Yamaha Speed Secrets,something like that,written around 1973...I use their specs to port an RD350 steet bike to the TR3 road racer specs,wow what a difference,no experimenting, the full data was there.
Sadly 2-stoke bikes are almost extinct now so most of that kind of info and data is long gone. I was horrified to see recently a lot of the newer MX bikes are 4-strokes-gag!!:msp_angry:

Maybe one day I could meet up with you in Victoria and we could see if the shop is still there and the guy is still around... As for a new piston,the old one is a full skirt design unlike modern motors,but I think Wiseco can modify a 4-stroke blank,before the ring grooves are cut,then they can cut me 2 grooves for pinned rings,not the 3 4-stroke ring grooves. To just go and make a new design piston is too much $$$(15 pistons min.),but they said they could probably make one for me from the blank of an existing similar piston. Anyway,no time or money for it now,it's a project for later,I have everything else to build it though. Of course the old Canadien will never be capable of competing in proffessional Loggers Sports(The crank and rod design are too weak I fear for real high revs) but it will be ok and fun to see in small local events.:msp_smile:

By the way,many years ago there was an old guy in this town who I knew and he had the biggest collection of running antique chainsaws I ever saw or heard of. He used to bring the odd one to the shop to show us. One day he brought a big Mercury twin cylinder 2-man saw and ran it,wow what a crazy looking thing,,twin fishtail mufflers,big bicycle handlebars, etc.,cool. Anyway he's passed away now,but I sometimes wonder where all his saws went... :bang:

Cool stuff man. I'd love to meet up someday. Ya I wonder what happened to his collection. It'll surface someday.

 

[young]

I know this has been done before, but with the search bein the way it is I though I'd start a new thread. I'll go through how I set up & read a degree wheel. The saw it's on is a Husky 576xp without the base gasket installed.

I bought a 1/2' drill chuck from Harbor freight to mount to my wheel.

Find a suitable place to mount the pointer.

I use a home made piston stop made from an old plug & a bolt.
[/img]http://i772.photobucket.com/albums/yy4/stump7997/saws050.jpg[/img]
Install the stop & turn the degree wheel both ways against the stop & right down the numbers. Add those numbers together then divide by 2. example 59+63=122; 122/2= 61. set the wheel @ 61. Double check by turning the wheel the other way to the stop. you should get the same reading on each side of the stop.

Once I git the wheel zeroed remove the stop & move on to the ex port. Turn the wheel in the same direction as the saw is running. Shine a light throught the plug hole, look fer the piston to just barely clear the top of the port. Look real close & set it to where the top of the piston is even with the top of the port. look @ the wheel & record the number. I've got 104* ATDC (after top dead center)

Now we know when the ex port opens we need to figure the duration or the amount of time the port is open during a complete revolution of the crank. Multiply the opening number by two, then subtract that number from 360 ( amount of degree's in a complete revolution). That number is the amount of time in degrees that the port is open. So 104*2=208 360-208=152. The exhuast port is open fer 152* of the each revolution.

A quick note about my pointer, the piont on it is not in the middle. It's on the left side of the wire. No real reason just the way it is fer now.

Lets move on to the transfer ports. They can be hard to see exactly when they open up. Some you can shine a light through the plug hole & look through the ex port to see when it opens. Others you have to do the opposite. You may also have to shine the light in the plug hole & look through the plug plug hole @ the same time. Just take yer time & try different angles til you are comfortable with the reading you came up with.
Basically the same as the ex port. Turn the crank the same direction as it runs till the piston is just even with the top of the port. record yer number & use the same math to find the duration fer the trans port. I've got 115* ATDC. SO 115 X 2 =230 360-230=130* of duration.

fixed you picture issue part 1

 

[young]

On to the intake. Keep turnin the crank in the same direction. Turn it past BDC (bottom dead center) till the bottom of the piston skirt is even with the bottom of the intake port. Record the reading. Now, on my wheel it reads a full 360 degrees. I have wrote the numbers on the wheel from 0-180 on that half of the wheel. I've come up with 106 degrees ABDC (after bottom dead center). 106 X 2=212 360-212=148* duration.

Since this is a stratto saw I'll include the pics fer the stratto ports. Keep tunin the crank till you can see the port openin up. record that reading. I've got 82*. 82 X 2=164 360-164=196* of duration.

fixed part2

 

[Stumpys Customs]

Thanks young, I wonder what happend?? They were fine earlier.