Valves should be lapped only with fine-grained lapping paste. A rubber suction cup, fixed to the valve plate, is used for lapping. To avoid the formation of grooves on the lapped surfaces during lapping, it is necessary to regularly tear the valve off the seat and turn the valve in both directions.
Note: After finishing the lapping process, it is necessary to carefully remove any remaining lapping paste.
The quality of the lapping is checked by the contact spot using Prussian blue, lead white or fuel. To do this, insert the valve and pour fuel into the combustion chamber. Fuel should not leak through the valve guide bushing. Otherwise, repeat the lapping process.
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