- Motorcycle clutches consist of many parts, which all work in unison to connect and disconnect the transmission from the engine. Main clutch parts are divided into Drive and Driven categories. Drive parts include the clutch hub and clutch plates, which are connected by teeth on the inner edge of the plate that mesh with outer hub splines. The clutch hub is connected to the engine sprocket by a chain or belt. Driven parts include the clutch basket and friction plates (plates with heat--resistant linings that grip clutch plate surfaces when pressed together). Metal fingers extending from the outer edge of the plates fit snugly into slots in the clutch basket. The basket is attached to the transmission's input shaft. Clutch and friction plates are arranged in alternating order so each friction plate contacts clutch plates on both sides. Together, the plates are sandwiched between the clutch basket and hub, teeth meshing with splines, and fingers meshing with slots, The force necessary to join the drive and driven parts is provided by either a large diaphragm spring or several smaller coil springs. Both styles apply spring force to a pressure plate, which, in turn, presses the clutch and friction plates together. This connection allows the clutch hub to drive the basket, transferring the engine's power to the transmission.
- Motorcycle clutch manufacturers utilize differing mechanical configurations to release and engage the clutch. These mechanisms release the spring pressure applied to the pressure plate, allowing the clutch plates to rotate at the same rate as the engine sprocket while the friction plates stop moving. Clutch levers are usually located on the left handlebar, and are connected to the release mechanism by a metal twisted--strand cable. This cable is equipped with adjusters that allow mechanics to adjust the clutch operation to the riders' preference.
- When the rider squeezes the clutch lever, the clutch cable activates the release mechanism, which releases the force applied to the pressure plate by the spring(s). The clutch and friction plates separate, and the engine operates without its power being delivered to the rear wheel. When the rider releases the clutch lever, the clutch cable activates the release mechanism in reverse. Spring pressure is reapplied to the pressure plate, and the clutch and friction plates are forced together, linking the drive and driven halves of the clutch and completing the connection between the motorcycle's engine and transmission. The engine's power is delivered through the clutch and transmission to the rear wheel, propelling the motorcycle until the clutch is again disengaged.