Universal Parts CVT Torque Spring | 139QMB 50cc venture rack Standard GY6 Guide Length: 228

Standard GY6 Guide Length: 228

Belt Size: 977-23

Universal Parts Rocker Arms for use on heads with 69mm Valves found on 50cc 4-stroke QMB139 engines

Compatibility: Models below and bikes with 2T horizontal Minarelli engines

Vee Rubber's 3/3

Universal Parts CVT Torque Spring | 139QMB 50cc venture rack Standard GY6 Guide Length: 228Restore proper CVT engagement and shift behavior on your 50cc scooter with this Universal Parts replacement torque spring for 139QMB 4 stroke engines. The torque spring sits inside the rear driven pulley (clutch side) of the CVT and controls the rate at which the belt rides up the pulley faces as engine load increases. A worn or fatigued spring causes sluggish acceleration, belt slip, and poor top speed engagement replacing it restores factory CVT