Yamaha YZF-R125 Service Manual: Checking the rectifier/regulator
1. Check:
Rectifier/regulator output voltage
Out of specification → Replace the
rectifier/
regulator.
a. Set the engine tachometer to the spark plug lead.
b. Connect the pocket tester (DC 20 V) to the
rectifier/regulator coupler as shown.
- Positive tester probe
red "1" - Negative tester probe
black "2"
c. Start the engine and let it run at approximately 5000 r/min.
d. Measure the charging voltage.
Checking the stator coil
1. Disconnect:
Stator coil coupler
(from the wire harness)
2. Check:
Stator coil resistance
Out of specification → Replace the
crankshaft
position sensor/stator assembly.
a. Conne ...
Checking the horn
1. Check:
Horn resistance
Out of specification Replace.
a. Disconnect the horn connectors from the
horn terminals.
b. Connect the pocket tester ( × 1) to the horn
terminals.
Positiv ...
Other materials:
Intake air pressure sensor
1. Check:
Intake air pressure sensor output voltage
Out of specification Replace the throttle
body.
a. Connect the pocket tester (DC 20 V) to the
throttle body sensor assembly coupler as
shown.
Positive tester probe
pink/white "1"
Negative tester probe
gray/black "2"
...
Checking the front brake hose
1. Check:
Brake hose "1"
Cracks/damage/wear
Replace.
2. Check:
Brake hose holder "2"
Loose connection Tighten the
holder bolt.
3. Hold the vehicle upright and apply the front
brake several times.
4. Check:
Brake hose
Brake fluid leakage Replace the
da ...
Circuit diagram
4. Main fuse
5. Main switch
9. Battery
25.ECU (engine control unit)
36.License plate light
37.Tail/brake light
44.Headlight relay
46.Pass switch
47.Dimmer switch
51.Headlight (low beam)
52.Auxiliary light
54.Headlight (high beam)
58.Meter light
60.High beam indicator light
64.Ignit ...