Sprocket Drive Key

The sprocket drive key is a small but critical component that locks the front engine sprocket to the engine output shaft. It sits in a machined keyway slot shared between the shaft and sprocket bore, preventing the sprocket from rotating independently of the shaft under load. Without it, the sprocket cannot transmit power reliably and will damage the shaft and sprocket in short order.

This is an OEM replacement part for the Rush SR. If you're removing or replacing the front engine sprocket, inspecting the drive key for wear or damage at the same time is good practice — a worn or sheared key is a straightforward fix when caught early and a much bigger problem if it isn't.