Troubleshooting - Yamaha YFZ450S 2003 Service Manual

EBS01045

TROUBLESHOOTING

The ignition system fails to operate (no
spark or intermittent spark).
Check:
1. fuse
2. battery
3. spark plug
4. ignition spark gap
5. ignition coil resistance
6. main switch
7. engine stop switch
8. throttle switch
9. carburetor switch
10.pickup coil resistance
11.wiring connections (of the entire ignition
system)
NOTE:
_
• Before troubleshooting, remove the following
part(s):
1. seat
2. fuel tank cover
3. side covers (left and light)
4. fuel tank
5. front fender
• Troubleshoot with the following special
tool(s).
Dynamic spark tester
P/N. YM-34487
Ignition checker
90890-06754
Pocket tester
P/N. YU-03112-C, 90890-03112
EBS01043
1. Fuse
• Check the fuse for continuity.
Refer to "CHECKING THE SWITCHES".
• Is the fuse OK?
YES
NO
Replace the fuse.
IGNITION SYSTEM
EBS01044
2. Battery
• Check the condition of the battery.
Refer to "CHECKING AND CHARGING
THE BATTERY" in chapter 3.
Minimum open-circuit voltage
12.8 V or more at 20 °C (68 °F)
• Is the battery OK?
EBS01032
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.
Standard spark plug
CR8E (NGK)
Spark plug gap
0.7 ~ 0.8 mm (0.028 ~ 0.031 in)
• Is the spark plug in good condition, is it of
the correct type, and is its gap within spec-
ification?
8 - 10
ELEC
YES
• Clean the battery
terminals.
• Recharge or
replace the battery.
YES
Re-gap or replace
the spark plug.
– +
NO
NO