What would cause my Sherco to shear 2 flywheel woodruff keys with in 1 hour? Bike is timed and fuel is good. New stator and electrics checked out by dealer not long ago. The bike ran for about 30 seconds then nothing!

the 2 faces of the taper will not be identical to each other .it doesnt take much .before fitting the woodruff key put a little valve grinding paste on the shaft,fit the flywheel and turn it back and forward until you get a nice light grey colour cn both faces then reassemble and it will be fine.it is not the woodruff key that keeps the flywheel from turning on the shaft it is the shaft itself the key is just a locator

Not much to add to that quote other than insuring the mating surfaces are properly torqued up with the nut which insures the proper interference fit.

This may require a proper holder for the flywheel and a torque wrench once the mating surfaces are assured good and clean. Look up moorse taper!

Do not try to over drive the nut to tighten things, as you may ruin the crank threads. Spec is 100nm or 73 lb/ft as I recall, but lookup to confirm.

Edited September 6, 201115 yr by copemech

thanks, I've been advised to use Sherco woodruff keys and torque the nut to the proper specs, so parts are ordered and found my torque wrench! So it should be in the sections soon! looks like the flywheel had loosened and took out the keys...

thanks to you all, the Sherco is back in 1 piece and going strong! Now to get the brakes working as they should!!!