Gary's right. You can't put just any flywheel on any engine. Typically the spoked flywheels that you're looking for are only used on 6/1 engines at 650 rpm. Some Indian assemblers include them on their 8/1 engines which run about 800 rpm. But the stover-type flywheels with the four equal diameter holes in the web are intended only for the 10/1 which operates at about 1000 rpm. If you put a 6/1 flywheel on a 10/1 engine, it will be out of balance, and the excessive speed may destroy the flywheel and the engine and possibly cause damage to anything/anyone nearby.
That said, I have a pair of new, unused 6/1 spoked flywheels that I have no need for. I'm in southern California and get up and down the length of the West coast every few months.
Quinn