Chainsaw Repair

you can run the same crank that everyone runs in the 3120 , 4 mm will fit using the 084 rod ,  if your running a 3120 crank you will need to open up the crankcase alot to get enough volume to pass enough air threw it , a 2100 crank fits the volume alot better but is more likely to break under load . If you want to cut metal you can pretty much put anything in a crankcase , I put a 3120 crank in a 281 crankcase just to see how it worked , ran ok but was not better that is forsure , just no room in the case with that big crank in it

EJ do you have a extra OEM (66mm) 090 jug for sale, Id be interested if you did. Ed had an awful go with the 70mm piston to cold start in the 3120 bottom end, maybe you guys will have better luck. Would make a high end hot start saw out west. 66mm are boss, but illegal half the places you go...so no go

Ed I believe the 54mm piston is of interest for  the Poulan 505 (?) same thing that Marcel made Jerry...a few carcasses are kicking around the web and there is interest in boost port with finger ports for a full fledge 5cu muffler.
I wonder why no one is talking about the 281/181 for the 5 cube another saw that needs no expensive crank work.

for a 5 cu muffler  the 181/281 is a hard saw to beat 

I think Jerry is now running a 372 saw in the 5 cu

Never been near that saw but I'm pretty sure I know what piston would be in it cause just about every small saw got that piston cause its the best piston made and that is the 52mm wide skirt 272 piston and I know Marcel never made any 54mm pistons but he made alot of those 52 mm pistons  so putting a 54 mm piston from a stock chainsaw would be going backwards , what you guys need to figure out is just because you can build a motor bigger does not make it faster , in alot of causes the saw ends up slower , crankcase volume is one of the biggest things you need to figure out to make a saw fast