Servicing; Cylinder Head And Valves - Kubota MX5100 Workshop Manual

MX5100, WSM

[3] SERVICING

(1) Cylinder Head and Valves

Top Clearance
1. Remove the cylinder head.
2. Move the piston up and stick a strip of fuse on the piston head at
three position with grease.
3. Lower the piston and install the cylinder head. (Use a new
cylinder head gasket and tighten with a specified tightening
torque.)
4. Turn the flywheel until the piston exceeds top dead center.
5. Remove the cylinder head and measure the thickness of the
fuses.
6. If the measurement is not within the factory specifications, check
the oil clearances between the crankpin and bearing and
between the piston pin and bushing.
NOTE
• After checking the top clearance, be sure to assemble the
cylinder head with a new cylinder head gasket.
Top clearance Factory spec.
Tightening torque Cylinder head screws
(1) Piston
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.
3. Measure the clearance with a feeler gauge.
4. If the measurement exceeds the allowable limit, correct it with a
surface grinder.
IMPORTANT
• Do not place the straightedge on the combustion chamber.
• Be sure to check the valve recessing after correcting.
Cylinder head surface
Allowable limit
flatness
1-S55
ENGINE
0.575 to 0.675 mm
0.0227 to 0.0265 in.
93.2 to 98.0 N·m
9.50 to 10.0 kgf·m
68.8 to 72.3 lbf·ft
(2) Fuse
W1020190
0.05 mm
0.002 in.
W1027737