6-7
PERIODIC MAINTENANCE AND MINOR REPAIR
6
When installing the plug, the gas-
ket surface should always be
cleaned and a new gasket used.
Any grime should be wiped off
from the threads and the spark
plug tightened to the specified
torque.
NOTE:
If a torque wrench is not available
when installing a spark plug, a
good estimate of the correct torque
is 1/4 to 1/2 turn past finger tight.
The spark plug should be tightened
to the specified torque as soon as
possible.
1
1.
Spark plug gap
EAU01651*
Spark plug inspection
The spark plug is an important
engine component and should be
inspected periodically, preferably
by a Yamaha dealer. The condition
of the spark plug can indicate the
condition of the engine. The ideal
color on the white insulator around
the center electrode is a medium-
to-light tan color for a motorcycle
that is being ridden normally. Do
not attempt to diagnose any prob-
lems yourself. Instead, take the
motorcycle to a Yamaha dealer.
The spark plug should be periodi-
cally removed and inspected
because heat and deposits will
cause the spark plug to slowly
break down and erode. If electrode
erosion becomes excessive, or if
carbon and other deposits are
excessive, the spark plug should
be replaced with the specified
plug.
Before installing the spark plug,
measure the electrode gap with a
wire thickness gauge and adjust it
to specification.
Specified spark plug:
D8EA (NGK)
X24ES-U (DENSO)
Spark plug gap:
0.6 ~ 0.7 mm (0.024 ~ 0.028 in)
Tightening torque:
Spark plug:
17.5 Nm (1.75 m
0
kgf,
12.7 ft
0
lbf)
3GX-9-33 (E) 12/10/07 11:17 AM Page 41
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