The CG125 cylinder set is the core assembly of a single-cylinder, four-stroke, air-cooled engine, used in 125cc commuter motorcycles. It consists of a cylinder body, piston, piston rings, piston pin, circlip, and upper and lower gaskets, responsible for completing the four-stroke cycle of intake, compression, power, and exhaust, serving as a key component for power output and efficiency. The three-ring piston design ensures cylinder sealing, reduces compression leakage and oil blow-by, and improves combustion efficiency. With proper maintenance, its lifespan can reach 20,000–30,000 kilometres, making it suitable for urban commuting and medium to short-distance riding.