Yamaha YP125R, Service Manual

Page: 400 / 498

IGNITION SYSTEM
8-3
EAS27120
TROUBLESHOOTING
The ignition system fails to operate (no spark or intermittent spark).
TIP
• Before troubleshooting, remove the following part(s):
1. Storage box
2. Front cowling
3. Storage compartment
4. Footrest board
NG
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OK
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OK
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OK
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NG
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OK
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OK
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1. Check the fuses.
(Main, ECU, and ignition)
Refer to “CHECKING THE FUS-
ES” on page 8-77.
Replace the fuse(s).
2. Check the battery.
Refer to “CHECKING AND
CHARGING THE BATTERY” on
page 8-78. • Clean the battery terminals.
• Recharge or replace the battery.
3. Check the spark plug.
Refer to “CHECKING THE SPARK
PLUG” on page 3-24. Re-gap or replace the spark plug.
4. Check the ignition spark gap.
Refer to “CHECKING THE IGNI-
TION SPARK GAP” on page 8-83. Ignition system is OK.
5. Check the spark plug cap.
Refer to “CHECKING THE SPARK
PLUG CAP” on page 8-82. Replace the spark plug cap.
6. Check the ignition coil.
Refer to “CHECKING THE IGNI-
TION COIL” on page 8-82. Replace the ignition coil.
7. Check the crankshaft position sen-
sor.
Refer to “CHECKING THE CRANK-
SHAFT POSITION SENSOR” on
page 8-83.
Replace the crankshaft position sen-
sor/stator assembly.