Kubota M5040, Workshop Manual

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1-S48
M5040, M6040, M7040, WSM ENGINE
Connecting Rod Cap
1. Remove the connecting rod screws (1) from connecting rod cap.
2. Remove the connecting rod caps.
(When reassembling)
• Align the marks (a) with each other. (Face the marks toward the
injection pump.)
• Apply engine oil to the connecting rod screws and lightly screw it
in by hand, then tighten it to the specified torque.
If the connecting rod screw won’t be screwed in smoothly, clean
the threads.
If the connecting rod screw is still hard to screw in, replace it.
• When using the existing crank pin metal again, put tally marks on
the crank pin metal and the connecting rod in order to keep their
positioning.
• Fit the crank pin metal in place : its centrally groove side toward
the connecting rod, and the non-grooved side toward the cap.
W1058252
Piston
1. Completely clean carbon in the cylinders.
2. Turn the flywheel and set a piston to the top dead center.
3. Pull out the piston upward by lightly tapping it from the bottom of
the crankcase with the grip of a hammer.
(When reassembling)
• Before inserting the piston into the cylinder, apply enough engine
oil to the cylinder.
• When inserting the piston into the cylinder, face the mark (2) on
the connecting rod to the injection pump.
IMPORTANT
Q
• Do not change the combination of cylinder and piston.
Make sure of the position of each piston by marking. For
example, mark “1” on the No. 1 position.
• When inserting the piston into the cylinder, place the gap of
each piston ring like the figure.
• Carefully insert the pistons using a piston ring compressor
(1). Otherwise, their chrome-plated section of piston rings
may be scratched, causing trouble inside the liner.
• When inserting the piston in place, be careful not to get the
molybdenum disulfide coating torn off its skirt (3). This
coating is useful in minimizing the clearance with the
cylinder liner. Just after the piston pin has been press-fitted,
in particular, the piston is still hot and the coating is easy to
peel off. Wait until the piston cools down.
W1058433
Tightening torque Connecting rod screw
68.6 to 73.5 N·m
7.0 to 7.5 kgf·m
50.6 to 54.2 lbf·ft
(1) Connecting Rod Screw (a) Mark
(1) Piston Ring Compressor
(2) Mark
(3) Molybdenum Disulfide Coating in
piston skirt
(a) 0.79 rad (45
°
)
(A) Top Ring Gap
(B) Second Ring Gap
(C) Oil Ring Gap
(D) Piston Pin Hole
(E) Injection Pump Side
KiSC issued 06, 2008 A