The Clutch fit 2 – 6.5 HP 168 188 Gasoline Engines for Generator and go kart, Single Wheel Drive Karts with Tires no larger than 15″ Tall Accepts 35# Chain (3/8″ chain pitch) 11 Tooth Sprocket Racing Centrifugal Clutch High Quality Go Kart Tractor Mini Bike Cyntrifical Clutch 5/8″ Bore Set Screws Not Included, Bi-directional operation, Easy to install Set screws and chain NOT included Go Kart Mini bike Centrifugal Clutch for Go-Karts, Riding Mowers, Snow Throwers (5/8″ Bore 11T)Specifications:Bore diameter: .625 inches (slightly smaller than a DimeFits:Centrifugal Clutch 11 tooth, 5/8″ bore,use 35# chainPredator 2.8 HP 97cc engine, some older 3hp enginesEngines with 5/8 inch (.625 inch) output shaft with standard keywaySet Screws NOT Included. Mounts onto crankshaft using bolt and washer on the end of the crankshaft.97cc 2.8 Hp Mini Baja Motorsports Mini Bike 11 Tooth 5/8″ Bore Clutch Assembly