6-8
PERIODIC MAINTENANCE AND MINOR REPAIR
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2. Use the spark plug wrench in
the tool kit to remove the spark
plug as shown.
Inspection
The spark plug is an important
engine component and is easy to
inspect. The condition of the spark
plug can indicate the condition of
the engine.
The ideal color on the white insula-
tor around the center electrode is a
medium-to-light tan color for a
motorcycle that is being ridden
normally.
Do not attempt to diagnose such
problems yourself. Instead, take
the motorcycle to a Yamaha deal-
er. You should periodically remove
and inspect the spark plug because
heat and deposits will cause any
spark plug to slowly break down
and erode. If electrode erosion
becomes excessive, or if carbon
and other deposits are excessive,
you should replace the spark plug
with the specified plug.
Installation
1. Measure the electrode gap
with a wire thickness gauge
and, if necessary, adjust the
gap to specification.
2. Clean the gasket surface. Wipe
off any grime from the
threads.
3. Install the spark plug and tight-
en it to the specified torque.
1.
Spark plug wrench
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1.
Spark plug gap
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Tightening torque:
Spark plug:
13 Nm (1.3 m
0
kg)
Spark plug gap:
0.7 ~ 0.8 mm
Specified spark plug:
CR9E (NGK) or
U27ESR-N (DENSO)
4PX-9-25-6(AUS) 4/17/0 12:43 PM Page 9