Twin Spark +R Superhead SCUT 136cc bore kit for the XR100R and CRF100F improves spark efficiency and combustion. Largest valves in class, and the proven forged aluminum roller rockers are included in this top of the line bore kit. 3 SR series cam choices make this kit more versatile than any other on the market.

• Bore: 62mm  Stroke: Stock 45mm
• Kit includes SR25 camshaft