Kubota WSM J Series Workshop Manual page 123

J SERIES, WSM
Valve Recessing
1. Clean the cylinder head surface, valve face and valve seat.
2. Insert the valve into the valve guide.
3. Measure the valve recessing with a depth gauge.
4. If the measurement exceeds the allowable limit, replace the
valve.
5. If it still exceeds the allowable limit after replacing the valve,
correct the valve seat face of the cylinder head with a valve seat
cutter (Code No. 07909-33102) or valve seat grinder. Then,
correct the cylinder head surface with a surface grinder, or
replace the cylinder head.
[Z482, D722]
Factory spec.
Valve recessing
Allowable limit
[D1005, V1305]
Factory spec.
Valve recessing
Allowable limit
(1) Cylinder Head Surface
Valve Lapping
1. Apply compound evenly to the valve lapping surface.
2. Insert the valve into the valve guide. Lap the valve onto its seat
with a valve flapper or screwdriver.
3. After lapping the valve, wash the compound away and apply oil,
then repeat valve lapping with oil.
4. Apply prussian to the contact surface to check the seated rate. If
it is less than 70%, repeat valve lapping again.
IMPORTANT

• When valve lapping is performed, be sure to check the valve
recessing and adjust the valve clearance after assembling
the valve.
(1) Correct
(2) Incorrect
S-77
ENGINE
0.10 (protrusion) to
0.10 (recessing) mm
0.0039 (protrusion) to
0.0039 (recessing) in.
0.30 (recessing) mm
0.0118 (recessing) in.
0.05 (protrusion) to
0.15 (recessing) mm
0.0020 (protrusion) to
0.0059 (recessing) in.
0.40 (recessing) mm
0.0157 (recessing) in.
(A) Recessing
(B) Protrusion
W10305870
(3) Incorrect
W10309820
KiSC issued 10, 2016 A