Yamaha TZR50, Owner'S Manual

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3. Remove the spark plug as
shown, using the spark plug
wrench, which is located in the
storage compartment. (See page
6-1).
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 electro-
de erosion and excessive carbon
or other deposits, and replace it if
necessary.
To install the spark plug
1. Measure the spark plug gap with
a wire thickness gauge and, if
necessary, adjust the gap to spe-
cification.
1. Spark plug gap
2. Clean the surface of the spark
plug gasket and its mating surfa-
ce, 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.
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. Howe-
ver, the spark plug should be tighte-
ned to the specified torque as soon
as possible.
4. Install the spark plug cap.
5. Install the panel.
Tightening torque:
Spark plug:
22.5 Nm (2.2 m•kgf, 16.3 ft•lbf)
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
1
Specified spark plug:
NGK / BR9 ES
PERIODIC MAINTENANCE AND ADJUSTMENT
6-12
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