Electrical; Ignition Timing; Spark Plug - Yamaha QT 50F Service Manual

If steering head needs adjustment
using steering nut wrench, adjust steer-
ing head fitting nut until steering head is
tight without binding when forks are
turned.
NOTE:
Excessive tightening of this nut will cause
rapid wear of ball bearings and races.
Re-check for looseness and freedom of
movement.
d. Tighten steering fitting bolt.
NOTE:
After completing steering adjustment make
certain forks pivot from stop to stop without
binding. If binding is noticed, repeat adjust-
ment.
2. Suspension
a. Check all suspension for proper opera-
tion.
b. Check all suspension for proper tight-
ness.
2-5. ELECTRICAL
A. Ignition Timing (C.D.I.)
1. Ignition timing is checked with timing
light by observing the position of the
stationary pointer marked on the crank-
case and the marks on the magneto
flywheel. Ignition timing of this
motorcycle is non adjustable,
for checking.
1. Mark 2. Stationary pointer
2. Checking the ignition timing
Using a timing light check to see that
the stationary pointer and mark on the
magneto flywheel, are aligned.
a. Remove the crankcase cover (L).
b. Connect the timing light to the spark
plug lead wire.
c. Start the engine and keep it running at
the specified speed. Use a tachometer
for checking.
Timing checking speed: 5,000 r/min
d. While running the engine at the spe-
cified speed, check to see that the sta-
tionary pointer is aligned with the mag-
neto mark. If the marks are out of align-
ment check to see that the woodruff
key is broken or crankshaft assembly is
out of alignment.
Ignition timing:
0.94 mm (0.037 in) B.T.D.C.
B. Spark Plug
The spark plug indicates how the engine is
operating. If the engine is operating correct-
ly, and the motorcycle is being ridden cor-
rectly, then the tip of the white insulator
around the positive electrode of the spark
plug will be a medium tan color. If the in-
sulator is very dark brown or black color,
then a plug with a hotter heat range might be
required. This situation is quite common
during the engine break-in period.
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