The key clutch is an advanced form of centrifugal clutch and is often mounted into the output close of the motor crankshaft. The clutch has two sheave faces; one which is laterally fastened (stationary sheave), and one which can shift in and out to engage the belt (moveable sheave). https://gearboxcvt86429.tribunablog.com/considerations-to-know-about-cvt-46740780