The primary clutch is a sophisticated method of centrifugal clutch and is typically mounted to your output end on the motor crankshaft. The clutch has two sheave faces; one that is laterally mounted (stationary sheave), and one which can move out and in to engage the belt (moveable sheave). https://gearbox-cvt20751.total-blog.com/not-known-details-about-gearbox-cvt-57629284