Industrial QMB139 Performance Racing Clutch Assembly

Industrial QMB139 Performance Racing Clutch Assembly is a direct replacement for 139QMB/GY6 50cc four-stroke scooters, designed to deliver firmer engagement and quicker throttle response under racing-style riding. This universal-style clutch assembly for QMB139 engines features a drive pulley with a 118 mm outer diameter, a clutch bore of 12 mm, and a 104 mm shoe diameter, paired with a 6901-RS bearing, and it weighs 4 lb, making it a compact upgrade that preserves overall drivetrain fitment. Specifically formulated for QMB139 engines (49cc/50cc), it is suitable for 139QMB-based platforms and is typically used to refresh worn clutch components in such scooters.