Checking The Spark Plug Cap; Checking The Ignition Coil - Yamaha 2009 YFM25RY Service Manual

Continuity
Positive tester probe → sky
blue "1"
Negative tester probe → black/
yellow "2"
No continuity
Positive tester probe → black/
yellow "2"
Negative tester probe → sky
blue "1"
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a. Disconnect the starting circuit cut-off relay
from the wire harness.
b. Connect the pocket tester (Ω × 1) to the
diode coupler as shown.
c. Check the diode for continuity.
d. Check the diode for no continuity.
TIP
When you switch the positive and negative
tester probes, the readings in the above chart
will be reversed.
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EAS28060

CHECKING THE SPARK PLUG CAP

1. Check:
• Spark plug cap resistance
Out of specification → Replace.
Resistance
10.0 kΩ
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a. Remove the spark plug cap from the spark
plug lead.
b. Connect the pocket tester (Ω × 1k) to the
spark plug cap as shown.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
ELECTRICAL COMPONENTS
c. Measure the spark plug cap resistance.
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EAS28090

CHECKING THE IGNITION COIL

1. Check:
• Primary coil resistance
Out of specification → Replace.
Primary coil resistance
0.18–0.28 Ω
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a. Disconnect the ignition coil connectors
from the ignition coil terminals.
b. Connect the pocket tester (Ω × 1) to the
ignition coil as shown.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe
Orange "1"
• Negative tester probe
Ignition coil base "2"
c. Measure the primary coil resistance.
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2. Check:
• Secondary coil resistance
Out of specification → Replace.
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