Kubota M108S, Workshop Manual

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1-S54
M108S, WSM ENGINE
Free Length and Tilt of Valve Spring
1. Measure the free length (B) with vernier calipers. If the
measurement is less than the allowable limit, replace it.
2. Put the spring on a surface plate, place a square on the side of
the spring, and check to see if the entire side is contact with the
square. Rotate the spring and measure the maximum (A). If the
measurement exceeds the allowable limit, replace.
3. Check the entire surface of the spring for scratches. Replace it,
if any.
W1063303
Valve Spring Setting Load
1. Place the valve spring on a tester and compress it to the same
length it is actually compressed in the engine.
2. Read the compression load on the gauge.
3. If the measurement is less than the allowable limit, replace it.
W1063470
Oil Clearance between Rocker Arm Shaft and Bearing
1. Measure the rocker arm bearing I.D. with an inside micrometer.
2. Measure the rocker arm shaft O.D. with an outside micrometer,
and then calculate the oil clearance.
3. If the clearance exceeds the allowable limit, replace the rocker
arm and measure the oil clearance again. If it still exceeds the
allowable limit, replace also the rocker arm shaft.
W1063697
Tilt (A) Allowable limit
1.0 mm
0.039 in.
Free length (B)
Factory
spec.
Intake
valve 35.1 to 35.6 mm
1.39 to 1.40 in.
Exhaust
valve 35.1 to 35.6 mm
1.39 to 1.40 in.
Allowable
limit
Intake
valve 34.6 mm
1.36 in.
Exhaust
valve 34.6 mm
1.36 in.
(A) Tilt (B) Free length
Setting load / setting
length
Factory
spec.
Intake
valve
63.5 N / 31.5 mm
6.48 kgf / 31.5 mm
14.3 lbf / 1.24 in.
Exhaust
valve
63.5 N / 31.5 mm
6.48 kgf / 31.5 mm
14.3 lbf / 1.24 in.
Allowable
limit
Intake
valve
45.9 N / 31.5 mm
4.68 kgf / 31.5 mm
10.3 lbf / 1.24 in.
Exhaust
valve
45.9 N / 31.5 mm
4.68 kgf / 31.5 mm
10.3 lbf / 1.24 in.
Oil clearance of rocker
arm shaft and bearing
Factory spec.
0.016 to 0.045 mm
0.00063 to 0.0017 in.
Allowable limit
0.15 mm
0.0059 in.
Rocker arm shaft O.D. Factory spec.
15.973 to 15.984 mm
0.62886 to 0.62929 in.
Rocker arm I.D. for shaft Factory spec.
16.000 to 16.018 mm
0.62993 to 0.63062 in.
KiSC issued 06, 2007 A