I dug out the old, original hs35 that I pulled off my first bike to replace with a similar unit. My plan is to fix all the messed up stuff, stripped bolt holes and whatnot, fix the ignition, carb and give it a nice coat of paint and new decals. The bore is nice enough and the piston is mostly guff-free.

But the crank has messed up threads. Many abusive attempts to beat the flywheel off have resulted in less-than-nice threads on the flywheels side. I’ve done an ok job cleaning them up but i’d feel better with better threads. I assume the crank is cast iron. Has anyone had any luck welding, turning, and recutting the threads on a crank?

I’ve got a few cranks from late model rotary mower engines, and could turn the main journals to fit the horizontal block, but they are longer on the flywheel side and have a different taper. Is there a points type flywheel that would work with this crank? Preferably a die cast zinc flywheel and not a heavy as hell cast iron one.

And when did they switch to the iron flywheel?