Remove the valve.
Remove deposits from the guide bushing with a thin awl.
Insert a new valve from the side of the combustion chamber. The end of the valve stem must be closed with a guide sleeve.
Check for play by rocking the valve back and forth.
To check, attach a steel ruler or dial indicator to the valve disc. The play should not exceed 0.5 mm.
If the backlash is too great, then the guide bushings can be turned and oversized valves with an increased stem diameter can be installed.
Attention: If the guide bushings are turned or replaced, the valve seat must also be machined.
If the guide bushings are so worn out that they can no longer be machined, replace them.
Press out with a mandrel on a press towards the combustion chamber.
Heat the cylinder head to 50°C and cool the new guides to -15°C.
Install the guide bushings using a mandrel on the press. Dimension A must be 13.5 mm.
After pressing in, the hole in the guide sleeve must be expanded to the required amount.