Service Manual

19
Always turn the cutter clockwise. Use both the
45° valve seat cutter and the 32° valve seat
cutter to adjust the valve seat so that it contacts
the middle of the valve face. The 32° valve seat
cutter removes material from the top of the seat.
The 45° valve seat cutter removes material from
the bottom of the seat. Be sure that when
finished the area where the valve contacts the
valve seat is from 3.8 to 5.0mm wide. To
complete the procedure, make a light pass with
the 45° valve seat cutter to remove any burrs
that may be on the edge of the seat. When
complete, use the marking compound to check
for concentricity. Make sure that there is good
contact all the way around the valve.
Apply lapping compound to the valve face and
insert the valve into the cylinder head. Use a
valve lapping tool (1) to finish surfacing the valve
and valve seat. Remove any remaining
compounds before assembling the cylinder
head. Make sure that the pushrods are firmly
seated in the lifters. After assembly, follow the
Engine Valve Lash – Adjust and the Cylinder
Pressure – Check procedures to ensure a
proper assembly.
Engine Valve Lash – Adjust
Operating the engine with an improper valve
adjustment can reduce engine efficiency. This
reduced efficiency could result in excessive fuel
usage and/or shortened engine component life.
Remove spark plug caps, spark plugs, valve
cover, and valve cover gasket.
Remove 3 screws to remove shield from the
shroud to access the flywheel.
Rotate the flywheel clockwise by hand to align
the mark to the shroud mark. This is top dead
center for cylinder 1 piston.
Measure the valve clearance with a feeler gauge
(3). Refer to the following chart.
Valve Clearance
Intake 0.015 ± 0.05mm
Exhaust 0.020 ± 0.05mm
If the clearance is outside of the tolerance
range, adjust the clearance as follows:
Loosen the locking nut (1). Turn the adjustment
nut (2) clockwise to decrease the gap. Turn the
adjustment nut (2) counterclockwise to increase
the gap. When the valve clearance is within
tolerance, tighten the locking nut to 10±1 N·m
(7.5±0.75 lbft).
Revolve the flywheel clockwise 270
o
to move
cylinder 2 piston to top dead center. Measure
the valve clearance and adjust if necessary.
Reinstall the valve cover gasket and valve
cover. Check the spark plug washers to ensure
proper working condition. If the washer is
damaged, replace the washer. Install the spark
plugs and tighten to 22 ± 2 N·m (16 ± 2 lbft). DO
NOT over tighten as this may damage the
engine. Install the spark plug caps.
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1
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