Flying Horse 48cc/66cc/80cc 2-Stroke Motorized Bicycle Engine Clutch Small Bevel Gear &ndash; Gas Bike Small Bevel Wheel The Small Bevel Wheel helps move the large bevel gear in most 2-stroke 48cc or 66/80cc motorized bike engines to engage the engine To install, uninstall the round column bolt from the center of the gear. From there, gently pry the gear off, and with a key, press the gear back on to the motor- now you're ready to ride