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The porcelain insulator around the center
electrode of each spark plug should be a me-
dium-to-light tan color (the ideal color when
the vehicle is ridden normally), and all spark
plugs installed in the engine should have a
similar color. If any spark plug shows a dis-
tinctly different color, the engine could be op-
erating improperly. Do not attempt to
diagnose such problems yourself. Instead,
have a Yamaha dealer check the vehicle.
If a spark plug shows signs of electrode ero-
sion and excessive carbon or other deposits,
it should be replaced.
Before installing a spark plug, the spark plug
gap should be measured with a wire thick-
ness gauge and, if necessary, adjusted to
specification.
Clean the surface of the spark plug gasket
and its mating surface, and then wipe off any
grime from the spark plug threads.
Specified spark plug:
NGK/CR9EB
1. Spark plug gap
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
Tightening torque:
Spark plug:
13 N·m (1.3 kgf·m, 9.6 lb·ft)
1
UBDW11E0.book Page 42 Wednesday, June 7, 2023 11:11 AM