50cc case reed conversion

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The main problem with doing this would be making sure the rod lengths, or the stroke is similar or the same between the two engines otherwise the piston might go too high in the cyl and hit the head, or it might go too low.

True. There's a complete cylinder/piston crankshaft/ needle bearings and rings for a Husky 372 on Ebay for about $90.

I believe this is the 52 cc engine variant my JonnyRed saw uses.

I'm thinking if I do another 48cc engine, I'll look into making a cylinder base adapter and see if any one local machine shop can press off the crank axles from the HT engine and press them into the 372 crank. According to my calculations, the Husky 372 would have a 37 mm throw at 42mm bore and should fit the cylinder spigot with some filing of the bolt down holes and an adaptor The upside, big ass pumper carb, an engine that pulls strongly from 3000 to 10K. and a unitzed cylinder with better porting and exhaust timing.

Needs more research but I believe it can be done.
 
aosom 3 ring piston for 60cc kinda weird if u ask me lol
 

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I'll look into making a cylinder base adapter ...
Needs more research but I believe it can be done.
seems very possible, if there is enough space to tap new mounting holes and think if this adapter would be 5mm or less thick, you could shave down the bottom of the jug to keep port timing the same and piston to head clearance. not too much different than a Holley to GM Quadrajet carb adapter plate. just the cyl studs have to go all the way thru the jug.
there's couple threads on ppl that tried different cylinders on HT bottom end
 
A husky 372 engine would run circles around a China girl! I promise it would be easier to put the whole chainsaw engine on the bike and build like a chain to chain reducer or belt drive. Would most likely perform better as well. Would be a cool challenge to undertake if a guy had a few spare China girls and chain saws laying around.
 
Just the balance factor alone of the chainsaws crank.. Could you imagine holding on to a CG and starting it and revving to 10k lol. There has to be a way to get a balanced crank in these CGs but it may require a centrifugal clutch if you get too light. Or some kind of heavier gear to act as sort of a flywheel. I'm thinking I'm going to have to use mine as the guinea pig after break in...
 
A husky 372 engine would run circles around a China girl! I promise it would be easier to put the whole chainsaw engine on the bike and build like a chain to chain reducer or belt drive. Would most likely perform better as well. Would be a cool challenge to undertake if a guy had a few spare China girls and chain saws laying around.
It would be nice if that were true but sadly that's not the case at all!Saw's are designed to perform a completly different task than our bike engines,Some folks do rebalence the crank and true it as I do, my preference is a factor of 40% and I true them the same as a blue printed crank would be done so there is no more than 10 thou out.You are right about needing a centrifugal clutch for the saw as they dont have the stroke or the inertia to handle the load down low very well but that limit's the usable rpm range and doesn't make it very streetable.Just for something to think about my china girl has a bmep of 7.7 bar or 112 psi,it runs at 185 psi for comp with .7 squish that's around 8.5:1 comp ratio witch adds torque for the single gear use. With the balence improved and the crank now able to spin woble free even with 11/30 gearing and a 26" wheel the engine spins10.6k loaded and will spin at 8k all day at 230f witch has me traveling at around 55 mph.
 
yeah, the while thing about single speed application it needs a broader torque curve. if too narrow, like hi perf dirtbikes they have 5 or 6 speed trannies. with a weighty flywheel, that can help but it'll become wider on whichever side
 
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