Checking The Ignition Spark Gap; Checking The Spark Plug Cap; Checking The Ignition Coil - Yamaha YZ 2015 Series Owner's Service Manual

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a. Disconnect the diode from the wire harness.
b. Connect the pocket tester (  1) to the di-
ode coupler as shown.
c. Check the diode for continuity.
d. Check the diode for no continuity.
1
Sb
G/B
2
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CHECKING THE IGNITION SPARK GAP

EASB291355
1. Check:
• Ignition spark gap
Out of specification  Perform the ignition
system troubleshooting, starting with step 4.
Refer to "TROUBLESHOOTING" on page 8-
4.
Minimum ignition spark gap
6.0 mm (0.24 in)
TIP
If the ignition spark gap is within specification,
the ignition system circuit is operating normally.
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a. Remove the spark plug cap from the spark
plug.
b. Connect the ignition checker "1" as shown.
Ignition checker
90890-06754
Oppama pet–4000 spark checker
YM-34487
2. Spark plug cap
3
R
R/L
4
8-62
ELECTRICAL COMPONENTS
c. Push the engine stop switch.
d. Measure the ignition spark gap "a".
e. Crank the engine by pushing the start switch
and gradually increase the spark gap until a
misfire occurs.
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CHECKING THE SPARK PLUG CAP

EASB291356
1. Remove:
• Spark plug cap
(from the spark plug lead)
2. Check:
• Spark plug cap resistance
Out of specification  Replace.
Spark plug cap resistance
10 k
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a. Connect the pocket tester (  1k) to the
spark plug cap.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
b. Measure the spark plug cap resistance.
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EASB291357

CHECKING THE IGNITION COIL

1. Disconnect:
• Ignition coil terminal
(from the sub wire harness)
• Spark plug cap
(from the ignition coil)
2. Check:
• Primary coil resistance
Out of specification  Replace.
Primary coil resistance
2.16–2.64 