Centrifugal clutch is 1″ bore 14 tooth design. Suitable for #40/41/420 roller chain, and up to 13hp horsepower A high quality and professional go karts clutch that high impact, wear resistant that is super durable. Easy to install, and the kind of dry clutch is unnecessary to be oiled. Specification??Horse Power: Up to 13 HP, Keyway: 1/4 inch, Outside Diameter: 4.74 inch, Engagement Speed: Up to 3200 RPM Compatibility: Fit for Go Kart, Mini Bike and Lawnmower Note:Two set screws are included in the bag, please open the bag with caution, it may drop out. Application –for Mini Bikes and Go Karts–Other applications Specifications: * Shaft Bore :1″ * Accommodates:#40/41/420 Chain * Tooth:14 Feature