Gates Powerlink Belt for 50cc – 250cc Scooters, ATVs, Go Karts COMPATIBILITY: 50cc 4-Stroke A/C (139QMB) Scooters – 669 or 729 150cc 4-Stroke A/C (GY6 157QMJ) Scooters – 742 or 743 Short Case 150cc 4-Stroke A/C (GY6 157QMJ) Scooters – 835 or 842 Long Case 150cc 4-Stroke A/C (GY6 157QMJ) ATVs, Go Karts – 828 250cc 4-Stroke L/C (CN250 172MM) Scooters – 906 or 918 Here you will find CVT belts from many manufacturers to fit ATVs, UTVs, Scooters, Mopeds & Buggies. Most belts are measured by circumference – width – angle of cut. Example: A 669-18-30 Belt is 669mm in circumference – 18mm in width and is cut at a 30 degree angle. Also nearly all Chinese 50cc scooters use 669-18-30 belts and most 150cc use 842-20-30 belts. The Linhai Yamaha 257cc and 300cc engine use a 871-22.5-30 belt. This can be found on virtually all Tank, Roketa, and SUNL scooters which show a 257cc or 260cc engine. Most scooters that have the 16″ wheels use a long case engine and take a 906-22.5-30 belt. This is not 100% guaranteed so if you are in doubt, take off the cover and measure the belt before you replace it.