Troubleshooting - Yamaha XF50W 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. crankshaft position sensor resistance
8. main switch
9. engine stop switch
10. sidestand switch(optional)
11. lean angle cut-off switch
12. wiring connections (of the entire ignition
system)
NOTE:
8 Before troubleshooting, remove the follow-
ing part(s):
1. Battery cover
2. Front cover
3. Side cover (right)
8 Troubleshoot with the following special
tool(s).
Ignition checker
90890-06754
YM-34487
Pocket tester
90890-03112
YU-03112-C
IGNITION SYSTEM
EAS00738
1. Main Fuse
• Check the fuse for continuity.
Refer to "CHECKING THE FUSE" in chap-
ter 3.
* Is the fuse OK?
YES
V
EAS00739
2. Battery
• Check the condition of the battery.
Refer to "CHECKING AND CHARGING
THE BATTERY" in chapter 3.
a
Minimum open-circuit voltage
12.8 V or more at 20°C (68°F)
• Is the battery OK?
YES
V
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.
Standard spark plug
CR7E (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 speci-
fication?
-i YES
\7
8-10
4
NO
Replace the fuse.
I
NO
• Clean the battery ter-
minals.
• Recharge or replace
the battery.
NO
I
Re-gap or replace the
spark plug.