Flying Horse 49cc 4-Stroke Motorized Bicycle Transmission Chain Sprocket Shaft &ndash; Gas Bike Transmission Chain Sprocket Shaft Replacement The 4-Stroke Transmission Chain Gear is made for 5G Flying Horse and most all Huasheng 4-stroke bicycle engine kit tranmissions This gear fits inside of the transmission of a 4-stroke motor to help pull the internal chain in order to move the bike. Note: these gears are made specifically for these transmissions, and