SUPPLEMENT --1981 MODEL
Valve and valve seat wear decreases valve clearance,
If valve clearance is not adjust-
ed, the wear will eventually cause the valves to remain
partly open, which lowers performance, burns the valves
and valve seats, and may cause serious engine damage.
Valve clearance for each valve should be checked and
adjusted in accordance with the Periodic Maintenance
Chart (p. 340) and any time that clearance may have
been affected by disassembly.
Be careful to adjust within the specified clearance.
Adjusting to a larger value will disturb valve timing
and cause engine noise.
Valve clearance must be checked when the engine is
cold (room or atmospheric temperature).
Valve Clearance Inspection
eRemove the fuel tank
eDisconnect the battery ground
eRemove the spark plugs.
eRemove the vacuum switch valve (US model) (p. 48).
eRemove the two lower
coils (p. 49)
eRemove the cylinder head cover (p. 65).
eRemove the alternator cover (p. 85). The cover need
not be removed completely from the crankcase, so the
alternator leads may be left connected.
eUsing a wrench on the alternator rotor bolt, turn the
crankshaft clockwise so that the "T" mark on the rotor
is aligned with the line mark in the upper part of the
pickup coil base plate.
Pickup Coil Base Plate
eCheck that the timing mark on the exhaust camshaft
sprocket is aligned with the cylinder head cover mating
surface on the front side of the exhaust camshaft. If
it is not, turn the crankshaft another turn until
"T" mark is aligned with the line mark again.
At this position, the
(extreme left) piston is at top
dead center (TDC) at the end of its compression stroke.
this ctankshaft (0°) position, measure the clear-
ance between the cam and the shim of the
exhaust valves. See Table N27.
eNext turn the crankshaft 1/3 turn (120°) Clockwise
and align the
mark on the rotor with the line mark.
this crankshaft (120°) position, measure the valve
clearance of the