To Check/Install Spark Plug - Yamaha XT250Z Owner's Manual

PERIODIC MAINTENANCE AND ADJUSTMENT
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1. Spark plug wrench
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To check the spark plug
1. Check that the porcelain insulator
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around the center electrode of the
spark plug is a medium-to-light tan
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(the ideal color when the vehicle is
ridden normally).
7 TIP
If the spark plug shows a distinctly dif-
ferent color, the engine could be oper-
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ating improperly. Do not attempt to
diagnose such problems yourself. In-
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stead, have a Yamaha dealer check
the vehicle.
2. Check the spark plug for elec-
trode erosion and excessive car-
bon or other deposits, and replace
it if necessary.
Specified spark plug:
NGK/DR7EA
To install the spark plug
1. Measure the spark plug gap with a
wire thickness gauge and, if nec-
essary, adjust the gap to specifica-
tion.
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1. Spark plug gap
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
2. Clean the surface of the spark plug
gasket and its mating surface, and
then wipe off any grime from the
spark plug threads.
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3. Install the spark plug with the
spark plug wrench, and then tight-
en it to the specified torque.
Tightening torque:
Spark plug:
18 Nm (1.8 m·kgf, 13.0 ft·lbf)
TIP
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 tight. However, the spark
plug should be tightened to the speci-
fied torque as soon as possible.
4. Install the spark plug cap.