Description Universal replacement kick start arm assembly for 50cc 139QMB scooters, including models from Baja Motorsports (the SC50 50cc) and countless other models of GY6 style gas scooters. This kick start arm is designed to be mounted on the right side of the engine. This kick start lever is commonly used on many different brands of 50cc gas street scooters. Specifications Mounting Hole Diameter: 1/2″ Arm Length: 6-1/2 Compatibility Baja Motorsports Sun City 50 (SC50/SC50P/SC50QJ/SC50S) Jonway YY50QT-3 Jonway YY50QT-5 4-Stroke Jonway YY50QT-6 4-Stroke Jonway YY50QT-10 4-Stroke Jonway YY50QT-21 4-Stroke Jonway YY50QT-28 4-Stroke Jonway YY50QT-29