The tightness of the valves is checked with kerosene, which must be poured into the combustion chambers. In this case, the leakage of kerosene through the seals (valve - valve seat) not allowed.
A device is required for stationary testing of valve tightness.
To check the tightness, do the following:
Thoroughly clean the seats and valves and place the cylinder head on a stand.
Insert the valves into their respective guide bushings and close the spark plug holes with plugs.
Install the device (2) to the position shown in the figure.
Press the lever hard (1) and supply air with a rubber bulb until the pressure gauge shows a pressure of 50 kPa. Within 10 seconds there should be no pressure drop. If the pressure drops, i.e., air leaks, it is necessary to grind the working chamfers of the valves and the seats on the cylinder head.
The valves are removed from the cylinder head using a tool.