The valves are ground only with fine-grained grinding paste. To ensure the necessary rotational movements, a rubber suction cup is installed on the valve plate. It is necessary to avoid scratches on the seating surfaces during the grinding process by frequently lifting and turning the valve.
Caution: After lapping, carefully remove the grinding paste.
The grinding process is controlled by appearance and also by fuel: insert the valve freely, fill the combustion chamber with fuel, fuel should not leak through the valve guide bushing. Otherwise, continue the grinding process.