Yamaha WR125R 2009, Service Manual

Page: 288 / 372

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. Battery cover
2. Rear fender
3. Fuel tank
NG
→
OK
↓
NG
→
OK
↓
NG
→
OK
↓
OK
→
NG
↓
NG
→
OK
↓
NG
→
OK
↓
NG
→
OK
↓
NG
→
OK
↓
1. Check the fuses.
(Main and ignition)
Refer to “CHECKING THE FUS-
ES” on page 8-65.
Replace the fuse(s).
2. Check the battery.
Refer to “CHECKING AND
CHARGING THE BATTERY” on
page 8-65.
• Refill battery fluid.
• Clean the battery terminals.
• Recharge or replace the battery.
3. Check the spark plug.
Refer to “CHECKING THE SPARK
PLUG” on page 3-7. Re-gap or replace the spark plug.
4. Check the ignition spark gap.
Refer to “CHECKING THE IGNI-
TION SPARK GAP” on page 8-70. Ignition system is OK.
5. Check the spark plug cap.
Refer to “CHECKING THE SPARK
PLUG CAP” on page 8-69. Replace the spark plug cap.
6. Check the ignition coil.
Refer to “CHECKING THE IGNI-
TION COIL” on page 8-70. Replace the ignition coil.
7. Check the crankshaft position sen-
sor.
Refer to “CHECKING THE CRANK-
SHAFT POSITION SENSOR” on
page 8-71.
Replace the crankshaft position sen-
sor/stator assembly.
8. Check the main switch.
Refer to “CHECKING THE
SWITCHES” on page 8-61. Replace the main switch.