See: 6MIK

6MIK have introduced the new Optima ‘Booster’ rear cover for Team Orion Racing, Performa Racing and Optima CRF engines. The rear crankcase cover features two internal channels increasing engine efficiency by feeding optimally the ports. In addition, thanks to a mixture less impacted by the movement of the conrod, the CRF engine offers an improved idle stability, fuel mileage and overall engine performance.