Flying Horse 48cc/66cc/80cc 2-Stroke Motorized Bicycle Engine Clutch Camshaft &ndash; Gas Bike Clutch Camshaft Replacement The Clutch Camshaft is helped by the clutch arm for your 2-stroke 48cc or 66/80cc motorized bike engine in order to engage and disengage your motor Installation is simple: uninstall your drive sprocket case cover. Slip the stock clutch arm off the camshaft and press on a new clutch arm. Bolt the drive sprocket case cover back on and you're ready to ride