What is the main fault of the flywheel and how to repair it?

November 03, 2022

The main faults of the flywheel after use are: wear of the working surface, wear or breakage of the gear ring.

If the flywheel working surface is severely ablated, uneven, or swayed, it can be checked with a dial indicator on the cylinder block. For the non-perpendicularity of the connecting end of the crankshaft and the flywheel facing the axis of the crankshaft, the runout value displayed by the dial indicator 34mm from the axis of the crankshaft should not be greater than 0.025mm. The bounce of the contact surface between the flywheel and the clutch friction plate should be no more than 0.1mm. If it exceeds the regulations, it should be repaired.

Repairing the flywheel working surface can be carried out on a lathe or a surface grinder. After grinding, it should meet the technical requirements, otherwise it should be scrapped.

If the flywheel teeth are worn or broken, they can be surfacing welded with low-carbon steel electrodes, and then restored to their original shape by fitter processing, without heat treatment.

If one or part of the flywheel teeth is broken, the ring gear can be removed and repaired by turning over and shifting it. Because the ring gear and the flywheel are in an interference fit, the ring gear must be heated (can be heated by a blowtorch), generally at about 300°C, and then punched down with copper milling. For the overturned ring gear, it is best to use a file to chamfer the end face to mesh with the starter gear.