6-9
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU01833
Checking the spark plug
The spark plug is an important
engine component, which is easy to
check. Since heat and deposits will
cause any spark plug to slowly erode,
the spark plug should be removed
and checked in accordance with the
periodic maintenance and lubrication
chart. In addition, the condition of the
spark plug can reveal the condition of
the engine.
To remove the spark plug
1. Remove the spark plug cap.
1
1.
Spark plug cap
To check the spark plug
1. Check that the porcelain insula-
tor around the center electrode
of the spark plug is a medium-to-
light tan (the ideal color when the
motorcycle is ridden normally).
NOTE:
If the 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.
2. Check the spark plug for elec-
trode erosion and excessive car-
bon or other deposits, and
replace it if necessary.
2. Remove the spark plug as
shown, with the spark plug
wrench included in the owner’s
tool kit.
1
1.
Spark plug wrench
Specified spark plug:
BR9ES (NGK)
BR8ES (NGK) (CH, A only)
3MB-9-E8 6/13/01 10:55 AM Page 46
