This Comet clutch has a 1" bore with 1/4" key broached into the hub.
**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.**