Troubleshooting - Yamaha VMX12 2001 Service Manual

EAS00737

TROUBLESHOOTING

The ignition system fails to operate (no
spark or intermittent spark).
Check:
1. main and ignition fuses
2. battery
3. spark plugs
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.neutral switch
11.sidestand switch
12.diode assembly
13.vacuum pressure sensor
14.wiring connections (of the entire ignition
system)
NOTE:
@
• Before troubleshooting, remove the following
part(s):
1) top cover
2) electrical components board
3) left side cover
4) rider seat
5) main switch cover
• Troubleshoot with the following special
tool(s).
@
Ignition checker
90890-06754
Pocket tester
90890-03112
EAS00738
1. Main and ignition fuses
• Check the main and ignition fuses for conti-
nuity.
Refer to "CHECKING THE FUSES" in
chapter 3.
• Are the main and ignition fuses OK?
YES
NO
Replace the fuse(s).
IGNITION SYSTEM
EAS00739
2. Battery
• Check the condition of the battery.
Refer to "CHECKING THE BATTERY" in
chapter 3.
Minimum open-circuit voltage
12.8 V or more at 20 °C
• Is the battery OK?
EAS00741
3. Spark plugs
The following procedure applies to all of the
spark plugs.
• Check the condition of the spark plug.
• Check the spark plug type.
• Measure the spark plug gap.
Refer to "CHECKING THE SPARK PLUGS"
in chapter 3.
Standard spark plug
DPR8EA-9 (NGK)
X24EPR-U9 (DENSO)
Spark plug gap
0.8 ~ 0.9 mm
• Is the spark plug in good condition, is it of
the correct type, and is its gap within speci-
fication?
8 - 11
ELEC
YES
• Clean the battery
terminals.
• Recharge or
replace the battery.
YES
Re-gap or replace
the spark plug.
– +
NO
NO