Thanks Piper & Dave.

I'm lucky that my flywheel has the slot cut in it for the woodruff key so the cone should sit o.k.

I thought I had this all understood after searching & reading every (I think) Ryobi thread I could find... but, I was recently pointed in the direction of Joe Guzzardi's web-site, "Teaching a weedwacker how to fly" ([link=http://www.geocities.com/CapeCanaveral/Lab/6216/sonof.html]Son of Weedwacker Site[/link]). Here he say's, quote, "The flywheel is made off balance in order to compensate for the mass of the engine's other moving parts.... grind off enough material from the opposite side to regain the original unbalanced condition. This seems to contradict almost every other post I've read which says the flywheel should be balanced 'normally', just like a prop. Help, I'm confused again!

Steve