I like the very thin snowflake-shaped lockwashers for flywheel bolts, particularly if you can find the ones with smooth outer edges and the teeth pointing inboard. A drop or two of blue LocTite can't hurt, whether or not lockwashers are used. Be sure all the holes are filled, or you'll get oil leakage from the crankcase into the clutch housing.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!