YBR125 motorcycle sleeve assembly, cylinder diameter 54MM, pin diameter 15MM, ring groove 1.01.02.0MM, perfect match YBR125 cylinder/piston, including piston + piston pin + spring + piston ring, one-stop with cylinder core components; The piston, pin and ring are precisely processed according to the original factory specifications, and the matching clearance between components is accurate to ensure the cylinder seal and the stability of power output; The piston is forged aluminum alloy + wear-resistant coating, and the piston ring is chrome plated gas ring + steel sheet oil ring, which has strong resistance to high temperature and abrasion, and is suitable for long-term high load working conditions. Piston ring division of labor sealing pressure + scraping oil, piston lightweight design to improve running smoothness, give consideration to power and economy.