YBR125 motorcycle chain top, the installation hole position, push rod size and YBR125 engine timing chain cabin fully match, directly replace the original chain top without adjusting the installation position; Built-in spring/hydraulic automatic tensioning structure, real-time compensation of the tension of the timing chain, ensure the chain and camshaft gear meshing precision, eliminate transmission abnormal noise; The push rod is made of quenched steel, and the shell is cast alloy. It is resistant to wear and impact, and suitable for high temperature and high pressure conditions in the engine room. Including fixing screws, sealing gaskets, one-stop installation of the required parts, save the trouble of separate procurement; Equipped with special gasket, after installation, tightly fit the engine room, prevent oil leakage, dust intrusion.