0B-8 Maintenance and Tune-Up:
Tappet Clearance Inspection and Adjustment
Z9J0110206041
Inspect tappet clearance
Every 200 hours (12 months)
Inspection
The tappet clearance specification is different for intake
and exhaust valves.
Too small a tappet clearance may reduce engine power,
too large a tappet clearance increases valve noise and
hastens valve and seat wear.
When the tappets are set to the specified clearance, the
engine will run without excessive noise from the valve
mechanism and will deliver full power. In this engine, the
tappet clearance is increased or decreased by replacing
the shim disc, made of a special wear resistant material,
fitted to the top of the tappet. Using the proper tools
provides for easy removal and installation of the shim
disc.
Tappet clearance adjustment should be checked and
adjusted:
• During scheduled periodic inspection.
• When valve mechanism is serviced.
• When camshafts are disturbed by removing them for
inspection.
1) Remove following parts:
• Engine lower side cover.
Refer to “Lower Side Cover Removal and
Installation” in Section 2A (Page 2A-3).
• Ring gear cover.
Refer to “Ring Gear Cover Removal and
Installation” in Section 1D (Page 1D-2).
• Ignition coils and spark plugs.
Refer to “Spark Plug Removal and Installation”
(Page 0B-6) and “Spark Plug Inspection and
Cleaning” (Page 0B-7).
2) Remove the cylinder head cover (1).
Refer to “Cylinder Head Cover Removal and
Installation” in Section 1D (Page 1D-2).
3) Rotate crankshaft counterclockwise to bring cam
nose vertical to shim surface.
4) Measure tappet clearances by inserting thickness
gauge between cam and shim surface.
CAUTION
This is a left hand (LH) rotation powerhead.
Rotate crankshaft counterclockwise to
prevent water pump impeller damage.
NOTE
• Rotate crankshaft and measure clearance
for each tappet respectively by bringing
cam nose vertical to shim surface.
• All tappet clearances can be measured
during two crankshaft rotations.
Special tool
(A): 09900–20803 (Thickness gauge)
Tappet clearance (cold engine condition)
IN.: 0.23 – 0.27 mm (0.009 – 0.011 in.)
EX.: 0.30 – 0.34 mm (0.012 – 0.013 in.)
5) If out of specification, adjust tappet clearance by
changing shim.
1
I9J011020048-01
“a”: 90°
(A)
“a”
I9J011020008-01
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