BGM 9 Port Sport 70cc Cylinder Kit for SYM Jet Basix / Jet4R / Jet X Sport / Shark 50.
To the uninitiated – a 2 stroke engine makes power by drawing fresh fuel and air through the intake ports, and expelling exhaust gases out of the exhaust port. A standard port-map has a number of intake ports around the cylinder with one large exhaust port. A 9 port configuration features two additional ‘booster’ exhaust ports to the top left and right of the main exhaust port. Because the exhaust gas can be expelled more quickly, a higher volume can be expelled per cycle of the piston – which means that the intake ports can also be increased in size to allow a greater volume of fresh fuel and air in. More volume in, more volume out – That’s how you make more power.