1″ bore designed for 6.5hp 212CC engines, Fit for Go Kart and Mini Bike, Lawnmower and Fun Kart, also it can be used for many other applicationsSprocket: 14 teeth,For Chain: #40/41/420,(chain not included)Centrifugal Clutch built in 14 tooth, 1″ bore, 40/41/420 chain with 3/16 keyMade of high quality iron material,which is lightweight, portable, sturdy, durable, maximum torque, wear-resisting and fast heat disationPackage included:1 x Go Kart Centrifugal ClutchProduct Description Specifications: Clutch Bore: 1″ Sprocket: 14 teeth Clutch Dia: 107mm Clutch Height: 56mm Chain: #40/41/420 Engagement Speed: 2200??200 RPM Recommended Engine: 2HP – 6.5HP, 1″ shaft with flat key This Kit Includes: 1x 14 teeth #40/41/420 chain centrifugal clutch(Set screw or chain not included)