Airsal cast iron cylinder kits add more depth to the Airsal product range. Greater attention has been paid here to the ports, the design of which has been taken form the Metrakit MK sports cylinders. A larger carb is not necessary, but the jetting should be changed. 50cc cast iron sports cylinder kits are on par with 50cc cylinders such as Top Performance. Approx. 2 bhp increase over the original. . Cylinder head supplied.