Yamaha YBR250 2007 Service Manual page 335

3. Charging voltage
• Connect the pocket tester (DC 20 V) to the
battery, as shown.
Positive tester probe--> battery positive
terminal
Negative tester probe --> battery negative
terminal
• Start the engine and let it run at
approximately 5,000 r/min.
• Measure the charging voltage.
Charging voltage
14.0 V at 5,000 rpm
NOTE:
Make sure the battery is fully charged.
• Is the charging voltage within
specification?
YES
The charging
circuit is OK.
CHARGING SYSTEM
NO
If the charging voltage
is above the standard,
replace the rectifier
(regulator).
If the charging voltage
is below the standard,
check the stator coil
resistance.
4. Stator coil resistance
• Disconnect the generator connector from
wiring harness.
• Connect the pocket tester (Ω x 1) to the
charging coils, as shown.
Positive tester probe --> white 1
Negative tester probe --> white 2
Positive tester probe --> white 1
Negative tester probe --> white 3
• Measure the stator coil resistance.
Stator coil resistance
0.42 ~ 0.62 Ω Ω Ω Ω Ω --> at 20ºC (68°F)
(between black and white)
• Is the stator coil OK?
5. Wiring
• Check the connections of the charging
system. Refer to "CIRCUIT DIAGRAM".
• Is the charging system's wiring properly
connected and without defects?
Replace the
rectifier/
regulator.
7-25
ELEC
YES
Replace the stator.
YES
Connect or repair the
charging system
wiring.
NO
NO