Yamaha XT250N 2000 Owner's Manual page 47

PERIODIC MAINTENANCE AND MINOR REPAIR
To check the spark plug
1. Check that the porcelain insula-
tor around the center electrode
1
of the spark plug is a medium-to-
light tan (the ideal color when the
2
motorcycle is ridden normally).
NOTE:
3
If the spark plug shows a distinctly
different color, the engine could be
4
defective. Do not attempt to diagnose
such problems yourself.
5
have a Yamaha dealer check the
motorcycle.
6 6
2. Check the spark plug for elec-
7
trode erosion and excessive car-
bon or other
8
replace it if necessary.
Specified spark plug:
9
DR8EA (NGK) or
X24ESR-U (DENSO)
a. Spark plug gap
To install the spark plug
Instead,
1. Measure the spark plug gap with
a wire thickness gauge and, if
necessary, adjust the gap to
specification.
Spark plug gap:
0.6–0.7 mm
deposits, and
2. Clean the surface of the spark
plug gasket and its mating sur-
face, and then wipe off any grime
from the spark plug threads.
3. Install the spark plug with the
spark plug wrench, and then
tighten it to the specified torque.
a
6-7
Tightening torque:
Spark plug:
17.5 Nm (1.75 m0kg)
NOTE:
If a torque wrench is not available
when installing a spark plug, a good
estimate of the correct torque is
1/4–1/2 turn past finger
However, the spark plug should be
tightened to the specified torque as
soon as possible.
4. Install the spark plug cap.
tight.