Checking The Spark Plug - Yamaha 2009 YW125Y Owner's Manual

Spark plug, checking<IXE>
PERIODIC MAINTENANCE AND ADJUSTMENT

Checking the spark plug

The spark plug is an important engine
component, which is easy to check.
1
Since heat and deposits will cause any
spark plug to slowly erode, the spark
2
plug should be removed and checked in
accordance with the periodic mainte-
nance and lubrication chart. In addition,
3
the condition of the spark plug can re-
veal the condition of the engine.
4
To remove the spark plug
5
1. Place the vehicle
centerstand.
2. Remove panel B. (See page 6-8.)
6
3. Remove the spark plug cap.
4. Remove the spark plug as shown,
7
with the spark plug wrench included
in the owner's tool kit.
8
9
EAUT1835
1
1. Spark plug wrench
To check the spark plug
on the
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 vehicle is
ridden normally).
TIP
If the spark plug shows a distinctly dif-
ferent color, the engine could be operat-
ing improperly. Do not attempt to diag-
nose such problems yourself. Instead,
have a Yamaha dealer check the vehicle.
2. Check the spark plug for electrode
To install the spark plug
1. Measure the spark plug gap with a
2. Clean the surface of the spark plug
3. Install the spark plug with the spark
6-46 6-9
erosion and excessive carbon or
other deposits, and replace it if nec-
essary.
Specified spark plug:
U22ESR-N (DENSO)
wire thickness gauge and, if nec-
essary, adjust the gap to specifi-
cation.
Spark plug gap:
0.7 ~ 0.8 mm (0.028 ~ 0.031 in)
gasket and its mating surface, and
then wipe off any grime from the
spark plug threads.
plug wrench, and then tighten it to
the specified torque.
Tightening torque:
Spark plug:
13 Nm (1.3 m • kgf, 9.4ft • lbf)
EAU1722A