Operation Manual

6-8
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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 condi-
tion 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 problems yourself.
Instead, take the motorcycle to a
Yamaha dealer. The spark plug
should be periodically 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 car-
bon and other deposits are exces-
sive, the spark plug should be
replaced with the specified plug.
Before installing the spark plug, mea-
sure the electrode gap with a wire
thickness gauge and adjust it to
specification.
When installing the plug, the gasket
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 speci-
fied torque as soon as possible.
1. Spark plug wrench
PERIODIC MAINTENANCE AND MINOR REPAIR
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Specified spark plug:
BR9ES (NGK)
Spark plug gap:
0.7 ~ 0.8 mm
Tightening torque:
Spark plug:
20 Nm (2.0 m0kg)
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1. Spark plug gap
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