Valve seat processing

Valve seats in the cylinder head with slight signs of wear and burnout can in principle be machined if the 15°bevel on the outer circumference of the valve seat sleeve is not disturbed. Otherwise, the cylinder head is replaced. Processing requires a suitable hand mill or milling machine.



To ensure perfect centering, the 45°surface must be especially carefully machined. To avoid damaging the cylinder head prematurely, remove only enough material to cover the full width of the seat.



At a 75°surface, slightly cut the lower edge of the exhaust valve seat sleeve at this angle.



At 15°face, cut at this angle the top edge of the seat sleeve so as to obtain the following dimension "A".



Saddle Width "A" must be between 1.4 and 2.5 mm.