Kubota WSM OC60-E2 Workshop Manual page 94

OC60-E2, OC95-E2, WSM
Width of Contact between Valve and Valve Seat
1. Check the contact between the valve face and valve seat.
2. If the contact is uneven or the width of contact A is excessively
large. Either repair or replace the valve and valve seat. Lap
the valve on its seat with lapping compound.
Valve seat width A Factory spec.
Correcting Valve Seat
1. Slightly correct the seat surface with a 0.79 rad (45 ) or 0.52
rad (30 ) valve seat cutter (1).
2. Fitting the valve, check the contact position of the valve face
and seat surface with red lead. (Visual check)
If the valve is used for a long period of time, it deviates to the
upper part of the valve face, causing the seat to contact.
3. Grind the seat surface with a 0.26 rad (15 ) valve seat cutter
so that the valve seat width contacts in the same dimensions
from the center of the valve face width.
4. Repeatedly lap the valve and seat until the seated rate is more
than 70%.
(1) Valve Seat Cutter
(2) Identical Dimensions
(3) Valve Seat Width
(a) 0.79 rad (45 ) or 0.52 rad (30 )
(b) 0.26 rad (15 )
(c) 0.26 rad (15 )
S-42
ENGINE
2.12 mm
0.0835 in.
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A : Check Contact
B : Correct Seat Width
C : Check Contact
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