The valves can only be ground using fine-grained paste. To impart the necessary rotational movements to the valve plate, install a rubber suction cup. The formation of grooves on the valve seat can be eliminated by frequently lifting the valve and rotating it evenly further during grinding.
Attention! Any remaining grinding paste must be carefully removed after finishing the lapping process.
The quality of grinding is checked by the appearance of the working surface using "Prussian blue" or "zinc white", as well as using fuel. Loosely install the valves, fill the combustion chamber with fuel. Fuel should not flow to the valve guide. Otherwise, repeat the grinding process.