If you need a complete QMB139 clutch assembly for your modern 50cc scooter or go kart, Monster Scooter Parts has just what you need This pulley assembly, (aka driver pulley or variator) comes complete as shown in the photos Description If you need a complete QMB139 clutch assembly for your modern 50cc scooter or go kart, Monster Scooter Parts has just what you need. This pulley assembly, (aka driver pulley or variator) comes complete as shown in the photos. The scooter part includes the clutch with pads, pulley, and clutch bell housing. This high quality clutch assembly is an excellent choice for the popular Baja Retro 50 (RT50) and Sun City 50 (SC50S – VIN number LWGT) scooters, as well almost any other scooter with a 50cc 4-stroke GY6 QMB139 engine. Also compatible with go karts that are equipped with QMB139 style engines. With our global network of parts manufacturers and suppliers, Monster Scooter Parts is able to offer our customers some of the very finest replacement scooter parts at the very best price around.