357xxp race build

[Chainsaw Jim]

I've decided to do another 357/272 for racing in the Michigan area. It is going to be a stock appearing saw with a muffler.

First order of business was splitting the case for clearancing.


A little clearancing for the intake block and carb.

Holes migrated far enough to line up.

 

[Chainsaw Jim]

Nothing left in the way.

 

[Chainsaw Jim]

I'm going to run a Tillotson HS on this one.
Throttle rod modified and in place.

This plastic v-stack is temporary.


I'll be able to incorporate a modified portion of the air filter horn to run the stock kill switch.

I have to grab bearings and seals tomorrow and then it'll be time to mount the degree wheel.

 

[qurotro]

Wow, that's a good thread!

 

[cus_deluxe]

cool jim!

 

[~WBF]

That thing is going to fly So it's a actually smaller bolt pattern than the 272 head. Wow I didn't know that.

I did a BB 372 once. That was a disaster. Turn the flywheel Grind outside of cylinder to fit. Couldn't keep the cylinder down. Made my own mount to upper handle bar.
Smooth and lots of power.

I here the first one you did was crazy

 

[Intoxsawcated]

Perfect lil firewood cutter

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[EvilRoySlade]

Leaving the crank stuffers in? I wonder if the case volume will limit your power at racing speeds. I’m very curious how this one turns out.

 

[stranter]

I like the look of this [emoji106]

 

[Chainsaw Jim]

Leaving the crank stuffers in? I wonder if the case volume will limit your power at racing speeds. I’m very curious how this one turns out.

Wouldn't racing speeds benefit from less time circulating in the case?
I know it won't be good on bearings at those speeds, so bottle priming enough to wet them really good will be necessary.

This one in the video has the stuffers in place. Would you consider it anywhere near racing speed? It seems to have comparable strength to anything I've ever ran under 80cc's, but I am disappointed that I didn't grab another 70cc saw to compare with that day.

 

[Mkinslow]

Wouldn't racing speeds benefit from less time circulating in the case?
I know it won't be good on bearings at those speeds, so bottle priming enough to wet them really good will be necessary.

This one in the video has the stuffers in place. Would you consider it anywhere near racing speed? It seems to have comparable strength to anything I've ever ran under 80cc's, but I am disappointed that I didn't grab another 70cc saw to compare with that day.

Could this be done on a 359 chassis with a 365 cylinder?

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[Chainsaw Jim]

Could this be done on a 359 chassis with a 365 cylinder?

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Removing the stuffer cups would basically make this chassis a 359, but the 365/372 cylinder is too wide at the base to make fit.

 

[Mkinslow]

Removing the stuffer cups would basically make this chassis a 359, but the 365/372 cylinder is too wide at the base to make fit.

Gotcha thanks

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[Mkinslow]

Removing the stuffer cups would basically make this chassis a 359, but the 365/372 cylinder is too wide at the base to make fit.

But it could be done with a 359 and 272 cylinder? Correct?

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[Chainsaw Jim]

But it could be done with a 359 and 272 cylinder? Correct?

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Yes

 

[XP_Slinger]

Cool build Jim. Thanks for taking the time to share

 

[Armbru84]

Wouldn't racing speeds benefit from less time circulating in the case?
I know it won't be good on bearings at those speeds, so bottle priming enough to wet them really good will be necessary.

This one in the video has the stuffers in place. Would you consider it anywhere near racing speed? It seems to have comparable strength to anything I've ever ran under 80cc's, but I am disappointed that I didn't grab another 70cc saw to compare with that day.

Tough to really tell without seeing it in some square wood where you can really time the cuts from saw to saw. Looks like it runs good!

 

[Chainsaw Jim]

I'm doing the muffler a little bit different this time. Instead of pounding an ms361 muffler into shape I decided to build one out of a pair of 272 and 372 cans.


I hacked off the backside of the 272 muffler and will weld it to the 372 one.


Then I'll hack up the front to make a patch. I'll cut it to match a good as I can so it looks factory. I'll also braze in a pair of tubes for the mount screws.

 

[Chainsaw Jim]

New bearings, new gasket, crankshaft/stuffer cups cleaned up, case back together and ready to get the degree wheel centered up.
Starting port degrees are ex109-tr132-in79

.050 off squishband... another .017 to go.

 

[Chainsaw Jim]

Here's a few more pics.

I went with a 272 piston this time. It fits wider on the rod and the gap lets the rod rub on the crank. I made a couple spacers to center it.



The port work is done and this thing is ready for assembly and a test fire. I haven't finished the muffler yet, but fortunately I can rob the one off my other hybrid.