I am getting a lot of vibration on a recently converted featherlite (say's 21cc) Have it on an goldberg ultimate. I removed the ignition and flywheel and run it on glow (3/4 straight methanol 1/4 mustang 10%) Runs good but so much shaking at any throttle. Used the cut down flywheel as base for prop adapter, so my added adapter lentht is centered and balanced ok. Prop is balanced ok. Anyone do any balancing to piston, and if so any guidelines? Other suggestions? Thanks, red