Kubota M5040, Workshop Manual

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1-S52
M5040, M6040, M7040, WSM ENGINE
[4] SERVICING
(1) Cylinder Head and Valves
Top Clearance
1. Remove the cylinder head (remove the cylinder head gasket
completely).
2. Bring the piston to its top dead center fasten 1.5 mm dia. 5 to 7
mm long fuse wires to 3 to 4 spots on the piston top with grease
so as to avoid the intake and exhaust valves and the combustion
chamber ports.
3. Bring the piston to its middle position, install the cylinder head,
and tighten the cylinder head screws to specification. (Head
gasket must be changed to new one).
4. Turn the crank shaft until the piston exceeds its top dead center.
5. Remove the cylinder head, and measure squeezed fuse wires for
thickness.
6. If the measurement is not within the specified value, check the oil
clearance of the crankpin journal and the piston pin.
W1049122
Cylinder Head Surface Flatness
1. Clean the cylinder head surface.
2. Place a straightedge on the cylinder head’s four sides (
A ), ( B ),
( C ) and ( D ) and two diagonal ( E ) and ( F ) as shown in the figure.
Measure the clearance with a feeler gauge.
3. If the measurement exceeds the allowable limit, correct it with a
surface grinder.
IMPORTANT
Q
• Be sure to check the valve recessing after correcting.
W1061323
Top clearance Factory spec.
0.60 to 0.80 mm
0.0236 to 0.0315 in.
Tightening torque
Cylinder head mounting
screw
186.3 to 196.1 N·m
19.0 to 20.0 kgf·m
137.4 to 144.6 lbf·ft
(1) Fuse
Cylinder head surface
flatness
Allowable limit
0.05 mm
0.0020 in.
KiSC issued 06, 2008 A