Yamaha 90280-03017-00 Genuine Woodruff Key

The Yamaha 90280-03017-00 Woodruff Key is a genuine OEM replacement for one of the most mechanically critical small components in a Yamaha powersports engine. The Woodruff Key seats in a matching slot between the crankshaft taper and flywheel hub, locking them in precise rotational alignment. That alignment determines ignition timing — get it wrong by even a few degrees and the engine will run poorly or not at all. Yamaha manufactures this key to exact specifications for the crankshaft slot geometry and shear strength profile of the specific models it serves, ensuring that the flywheel seats and torques down exactly as engineered.

This part becomes necessary after any event that stresses the flywheel-to-crank interface — a hard crash, a hydrolocked or seized start attempt, or simply discovering a failed key during routine maintenance. Diagnosis is straightforward: a sheared or deformed key produces timing-related symptoms like hard starting, misfires, backfiring, or sudden power loss. Replacement is a precision job that requires proper flywheel removal tooling, but the repair itself is uncomplicated once the flywheel is off. Because this is a genuine Yamaha part rather than an aftermarket equivalent, mechanics and owners can install it with confidence that tolerances are correct and the key will perform exactly as the original did.