[GOSFAST]

Hi Henry, I'm assuming you've tried running the unit without the belt(s), eliminating all the "driven" pieces??

You really should inspect the flywheel/clutch ass'y very closely first, this means having a very reputable shop with a decent balancer run up both pieces.

We recently went through this dilemma with a customer in Maryland, he sent his flywheel/clutch ass'y to us for evaluation. We hadn't seen either piece before. Both were new and neither piece was balanced correctly. They were even worse when bolted together. We balanced the setup as a unit, indexed everything, and returned it. It WAS his problem, upon running up the pieces we knew it immediately. The balancer doesn't lie!

One more item to remember, when working with a 14"/18" wheel ANY imbalance present is much worse at the 7"/9" radius than the 3" crank radius! It is much more critical at that span. You will tend not to "feel" a 10 gram imbalance at 3", you WILL at 7"/9" out!

Thanks, Gary in N.Y.

P.S. When you are working with all stock (internal) components there should not be a single issue changing components, you should be able to interchange cranks, rods, and even pistons. Should have no noticeable adverse effects. Resizing rods will have no effect, "cutting" the crank to an undersize will have no effect. Not "balance-wise"!