This Comet clutch has a 1" bore with keyway that steps down to a 7/16" bore. 

• #35 has a 12T sprocket
• #41 has a 10T sprocket - Currently out of stock
  

**There are many variables that play into the performance of a clutch. Tire size, rear sprocket size and rear drive set-up are a few of the main variables that could affect clutch performance. If you are using large tires or a small sprocket, your vehicle may require a belt drive system. Clutch performance is not based soley on the engine size.**