Flying Horse 48cc/66cc/80cc 2-Stroke Motorized Bicycle Engine Gear Case Cover &ndash; Gas Bike Engine Cover Replacement The Gear Case Cover fits 48cc and 66/80cc motorized bicycle motors and houses the bevel gear assembly and small bevel gear that engages your motor Installation is a breeze: unbolt your stock gear case cover, remove, replace with the new cover, bolt down the cover, and you're ready to ride