6-7
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU01880
Checking the spark plugs
Spark plugs, checking
The spark plugs are important engine
components, which should be
checked periodically, preferably by a
Yamaha dealer. Since heat and
deposits will cause any spark plug to
slowly erode, they should be
removed and checked in accordance
with the periodic maintenance and
lubrication chart. In addition, the con-
dition of the spark plugs can reveal
the condition of the engine.
The porcelain insulator around the
center electrode of each spark plug
should be a medium-to-light tan (the
ideal color when the motorcycle is rid-
den normally), and all spark plugs
installed in the engine should have
the same color. If any spark plug
shows a distinctly different color, the
engine could be defective. Do not
attempt to diagnose such problems
yourself. Instead, have a Yamaha
dealer check the motorcycle.
Clean the surface of the spark plug
gasket and its mating surface, and
then wipe off any grime from the
spark plug threads.
a. Spark plug gap
If a spark plug shows signs of elec-
trode erosion 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 thickness gauge and, if
necessary, adjusted to specification.
Tightening torque:
Spark plug:
17.5 Nm (1.75 m·kgf)
Specified spark plug:
DPR8EA-9 (NGK) or
X24EPR-U9 (DENSO)
Spark plug gap:
0.8–0.9 mm
5PS-28199-E1 8/29/02 9:16 AM Page 52
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