Checking The Spark Plug - Yamaha Bws YW125 Owner's Manual

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 pe-
riodic 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. Place the vehicle on the center-
stand.
2. Remove panel B. (See page 6-7.)
3. Remove the spark plug cap.
4. R e m o v e t h e s p a r k p l u g a s
s h o w n , w i t h t h e s p a r k p l u g
wrench included in the owner's
tool kit.
PERIODIC MAINTENANCE AND ADJUSTMENT
EAUT1835
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1. Spark plug wrench
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
vehicle is ridden normally).
TIP
If the spark plug shows a distinctly
different color, the engine could be
operating improperly. Do not attempt
to diagnose such problems yourself.
Instead, have a Yamaha dealer check
the vehicle.
2. Check the spark plug for elec-
Specifi ed spark plug:
To install the spark plug
1. Measure the spark plug gap with
Spark plug gap:
2. Clean the surface of the spark
3. Install the spark plug with the
Tightening torque:
6-8
trode erosion and excessive
carbon or other deposits, and re-
place it if necessary.
U22ESR-N (DENSO)
a wire thickness gauge and, if
necessary, adjust the gap to
specifi cation.
0.7 ~ 0.8 mm (0.028 ~ 0.031 in)
plug gasket and its mating sur-
face, and then wipe off any grime
from the spark plug threads.
spark plug wrench, and then
tighten it to the specifi ed torque.
Spark plug:
13 Nm (1.3 m·kgf, 9.4 ft·lbf)
EAU1722A
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