Valves may be lapped only using fine-grained grinding paste. To perform the necessary rotational movements, a tool with a rubber suction cup is installed on the valve plate. The formation of scratches on the seat chamfers during lapping is eliminated by frequently lifting and uniformly turning the valve.
Warning: Grinding paste must be thoroughly removed after lapping.
The appearance of the working surface during the grinding process can also be controlled using fuel: insert the valve, fill the combustion chamber with fuel - the fuel should not flow out of the valve guide. Otherwise, repeat the grinding process.