Slipper clutch

A slipper clutch (also known as a back-torque limiter) is a specialized clutch with an integrated freewheel mechanism, developed for performance-oriented motorcycles to mitigate the effects of engine braking when riders decelerate.

The main purpose of a slipper clutch is to prevent over engine rev and rear wheel hop (or clatter) especially under hard braking in a vehicle (usually performance motorcycles). It does so by partially slipping until the engine's speed matches with the vehicle's speed upon sudden braking.