Checking The Spark Plug Cap; Checking The Ignition Coil - Yamaha YZ 2019 Series Owner's Service Manual

2. Spark plug cap
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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EAM30295

CHECKING THE SPARK PLUG CAP

1. Remove:
• Spark plug cap
(from the spark plug lead)
2. Check:
• Spark plug cap resistance
Out of specification  Replace.
Resistance
7.50–12.50 k
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a. Connect the digital circuit tester () to the
spark plug cap.
Digital circuit tester (CD732)
90890-03243
Model 88 Multimeter with tachom-
eter
YU-A1927
b. Measure the spark plug cap resistance.
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ELECTRICAL COMPONENTS
EAM30296

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 
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a. Connect the digital circuit tester () to the ig-
nition coil.
Digital circuit tester (CD732)
90890-03243
Model 88 Multimeter with tachom-
eter
YU-A1927
• Positive tester probe 
Ignition coil terminal 1 "1"
• Negative tester probe 
Ignition coil terminal 2 "2"
b. Measure the primary coil resistance.
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3. Check:
• Secondary coil resistance
Out of specification  Replace.
Secondary coil resistance
8.64–12.96 k
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a. Connect the digital circuit tester () to the ig-
nition coil.
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