Troubleshooting - Yamaha YP400T Service Manual

EAS00736

TROUBLESHOOTING

The ignition system fails to operate (no
spark or intermittent spark).
Check:
1. main and ignition fuses
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
11.starting circuit cut-off relay
12.lean angle cut-off switch
13.wiring connections (of the entire ignition
system)
NOTE:
_
• Before troubleshooting, remove the following
part(s):
1. storage box
2. front cowling
• Troubleshoot with the following special
tool(s).
Ignition checker
90890-06754, YM-34487
Pocket tester
90890-03112, YU-03112-C
EAS00738
1. Main and ignition fuses
• Check the main and ignition fuses for con-
tinuity.
Refer to "CHECKING THE FUSES" in
chapter 3.
• Are the main and ignition fuses OK?
YES NO
Replace the fuse(s).
8 - 9
IGNITION SYSTEM
EAS00739
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?
YES
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 spec-
ification?
YES
– +
ELEC
NO
• Clean the battery
terminals.
• Recharge or
replace the battery.
NO
Re-gap or replace
the spark plug.