Operation Manual

PERIODIC MAINTENANCE AND MINOR REPAIR
6-7
6
EAUT0004*
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 mainte-
nance and lubrication chart. In addition,
the condition of the spark plug can re-
veal the condition of the engine.
To remove the spark plug
1. Remove panel A. (See page 6-4
for panel removal and installation
procedures.)
2. Remove the spark plug cap.
3. Remove the spark plug as shown,
with the spark plug wrench includ-
ed in the owner’s tool kit.
To check the spark plug
1. Check that the porcelain insulator
around the center electrode of the
spark plug is a medium-to-light tan
(the ideal color when the motor-
cycle is ridden normally).
NOTE:
_
If the spark plug shows a distinctly dif-
ferent color, the engine could be defec-
tive. Do not attempt to diagnose such
problems yourself. Instead, have a
Yamaha dealer check the motorcycle.
_
2. Check the spark plug for electrode
erosion and excessive carbon or
other deposits, and replace it if
necessary.
1. Spark plug cap 1. Spark plug wrench
Specified spark plug:
CR7HSA (NGK)
U5MXE0.book Page 7 Thursday, December 20, 2001 2:08 PM