Yamaha VIKING Owner's Manual page 133

1. Spark plug wrench
Inspection
The spark plug is an important engine compo-
nent 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:
CPR7EA-9 (NGK)
8-23
1
2
3
4
5
6
7
8
9
10
11
12
13
14