To Check/Install Spark Plug - Yamaha MT-03 Owner's Manual

2. Remove the spark plug as shown,
with the spark plug wrench includ-
ed in the owner's tool kit.
To check the spark plug
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 vehi-
cle is ridden normally).
NOTE:
If the spark plug shows a distinctly dif-
ferent color, the engine could be defec-
tive. Do not attempt to diagnose such
problems yourself. Instead, have a
Yamaha dealer check the vehicle.
2. Check the spark plug for elec-
trode erosion and excessive car-
bon or other deposits, and re-
place it if necessary.
Specified spark plug:
CR7E (NGK)
PERIODIC MAINTENANCE AND MINOR REPAIR
To install the spark plug
1. Measure the spark plug gap with
a wire thickness gauge and, if
necessary, adjust the gap to
specification.
1. Spark plug gap
Spark plug gap:
0.7-0.8 mm (0.028-0.032 in)
6-7
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 tight-
en it to the specified torque.
Tightening torque:
Spark plug:
12.5 Nm (1.25 m·kgf, 9.0 ft·lbf)
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 tight. However, the
spark plug should be tightened to the
specified torque as soon as possible.
4. Install the spark plug cap.
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