The CG125 piston is the core moving component of a 125cc single-cylinder four-stroke pushrod engine, responsible for the compression of the air-fuel mixture, transmission of combustion pressure, and sealing of the cylinder. It is suitable for the CG125 and other 125cc platform motorcycles. The main body is made of high-silicon aluminium alloy, offering lightweight and good thermal conductivity. The skirt is often graphite-coated or anodised to reduce friction and enhance wear resistance. It consists of the piston crown, piston head, piston skirt, and pin boss. The top is flat to match the combustion chamber, the head has two compression ring grooves and one oil ring groove, the skirt is oval-shaped to compensate for thermal expansion, and the pin boss is for installing the piston pin and provides a circlip groove.