CG125 motorcycle crankshaft pin key, size (13.7×4.3×3.8MM) and CG125 crankshaft pin keyway exactly match, directly replace the original pin key, no need to adjust the crankshaft/gear assembly structure; Using high quality steel processing, high hardness, shear resistance, can withstand the transmission torque of the crankshaft and gear stably, not easy to deformation and fracture; After removing the crankshaft gear, insert the pin key into the crankshaft keyway, and then install the gear back to complete the installation (professional operation is recommended); It is fully compatible with the keyways of CG125 crcrshaft, clutch gear and other components, and the transmission meshing is accurate without lag after installation.