Yamaha VIKING 2021 Owner's Manual page 117

1. Spark plug cap
3. Use the spark plug wrench to remove the
spark plug as shown.
1. Spark plug wrench
Inspection
The spark plug is an important engine com-
ponent and is easy to inspect. The condition
of the spark plug can indicate the condition of
the engine.
1
The ideal color of the porcelain insulator
around the center electrode is a medium-to-
light tan for a vehicle that is being ridden nor-
mally.
You should periodically remove and inspect
the spark plug because heat and deposits will
cause the spark plug to slowly break down
and erode. If electrode erosion becomes ex-
cessive, or if carbon and other deposits are
excessive, you should replace the spark plug
with the specified plug.
Specified spark plug:
1
NGK/CPR7EA-9
Measure the spark plug gap with a wire thick-
ness gauge and, if necessary, adjust the gap
to specification.
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