Yamaha VINO YJ50RAP, Owner'S Manual

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6-6
PERIODIC MAINTENANCE AND MINOR REPAIR
6
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
scooter is ridden normally).
NOTE:
If the spark plug shows a distinctly
different color, the engine could be
defective. Do not attempt to diagnose
such problems yourself. Instead,
have a Yamaha dealer check the
scooter.
2. Check the spark plug for elec-
trode erosion and excessive car-
bon 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
specification.
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.
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.
Specified spark plug:
BPR7HS (NGK)
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
Tightening torque:
Spark plug:
20 Nm (2.0 m·kgf, 14 ft·lb)
a
a. Spark plug gap