Motorcycle One Way Starter Clutch Bearing compatible with models including 660 700 YZF R1 1000 XT660 XT600E TT600E TT600RE.This starter clutch bearing is designed for use in motorcycle engines where one-way engagement of the starter mechanism is required.It allows the starter motor to engage the engine during startup and disengage once the engine is running.The unit fits into the starter drive system and works as a mechanical switch between the starter gear and the engine crankshaft.Proper function starting and prevents damage to the starter motor.This bearing is built to match the specifications of the designated motorcycle models for direct replacement.