Is a torque converter the answer?


New Member
I keep having trouble with my scratch built mini bike throwing the chain. It usually only happens when I give it full acceleration. I have done all the usual - aligning, tightening, etc. It will stay on fine as long as I just start slow and go about half throttle.

I bought an idler pulley, but there isn't a good place to mount it. I'm still considering that.

I wonder if the engine plate is flexing because you can see the slack in the chain come down hard when accelerating, so maybe I should weld a support under the 1/8" tread plate to stiffen it?

Would I fix the problem by replacing the clutch with a torque converter? I am using a HF clone 212 engine.

If I could fix this problem I would really enjoy the bike!

Any help is appreciated.
Post some pics of the setup . If all is right she shouldn't throw the chain . How long is the setup ? A torque converter will still need a chain and this could still happen .
id say support the plate. youll never get away from the flex if you dont. might even be worse with a torque converter. what i usually do is weld a round pipe at the front and back of the engine plate that way it looks factory. idler pulley will probrobly fix it especially if its spring loaded. but the flex should really be fixed the right way
My first TrailHorse did the same thing. By adding the jackshaft it took the long length of the chain and made it two shorter chains so it wouldn't bounce. Also allows you to change your gearing if needed.
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New Member
To give some closure to this thread, I added a simple idler sprocket and so far it has solved the problem of throwing the chain!