Fits 50cc/100cc 4 Stroke GY6/QMB139 engines (6) 5 grams roller weights (3) 7 grams roller weights Rollers can be combined to achieve 5,6 and 7 grams setups. Improves acceleration and top end speed compared to stock/restricted cvt. High-Performance Racing Variator Kit for Chinese Scooter Moped ATV 4-Stroke GY6 50cc 80cc 100cc 139QMB 139QMA Engine Front Clutch Racing variator kit for 50/100cc 4 Stroke enginesBetter performanceImproves acceleration and top-end speed compared to stock/restricted CVTFits 50cc/100cc 4 Stroke GY6/QMB139 enginesInexpensive replacement for OEM variatorUpdates CVT and rear clutch Includes: (6) 5 grams roller weights (3) 7 grams roller weightsRollers can be combined to achieve 5,6 and 7 grams setups.3 slidersCVT Fan3 1000 RPM clutch springs for the rear clutchCVT shaft