Troubleshooting - Yamaha YJ50RAP Service Manual

EAS00736

TROUBLESHOOTING

The ignition system fails to operate (no
spark or intermittent spark).
Check:
1. main fuse
2. battery
3. spark plug
4. ignition spark gap
5. spark plug cap resistance
6. ignition coil resistance
7. pickup coil resistance
8. main switch
9. engine stop switch
10.wiring (of the entire ignition system)
NOTE:
@
• Before troubleshooting, remove the following
part(s):
1) center cover
2) side cover (left)
3) side cover (right)
4) leg shield
• Troubleshoot with the following special
tool(s).
Dynamic spark tester
YU-34487
Pocket tester
YU-03112
EAS00738
1. Main fuse
• Check the main fuse for continuity.
Refer to "CHECKING THE FUSE" in chap-
ter 3.
• Is the main fuse OK?
YES
Replace the main
fuse.
IGNITION SYSTEM
EAS00739
2. Battery
• Check the condition of the battery.
Refer to "CHECKING AND CHARGING
THE BATTERY" in chapter 3.
• Is the battery OK?
EAS00740
3. Spark plug
• Check the condition of the spark plug.
• Check the spark plug type.
• Measure the spark plug gap.
Refer to "CHECKING THE SPARK PLUG"
in chapter 3.
• Is the spark plug in good condition, is it of
the correct type, and is its gap within spec-
ification?
NO
7 - 9
ELEC
Minimum open-circuit voltage
12.8 V or more at 20 °C (68 °F)
YES
• Clean the battery
terminals.
• Recharge or
replace the bat-
tery.
Standard spark plug
BPR7HS (NGK)
Spark plug gap
0.6 ~ 0.7 mm (0.02 ~ 0.03 in)
YES
Re-gap or replace
the spark plug.
– +
NO
NO