[DavidNJ]

The flywheel comes balanced to the rotating assembly: 0, 28 oz-in, 50 oz-in. Anything really high reving should be internally balanced if possible. Although that is difficult with a short stroke crank and heavy rotating pieces.

The problem with the lightweight stuff comes when moving from rest and light throttle, low engine speed stuff. The inertia keeps it from stalling. With low inertia, you need more finesse on the throttle and clutch.