Yamaha YZF-R125 Service Manual: Electrical components
1. Main switch
2. Clutch switch
3. Front brake light switch
4. Ignition coil
5. Throttle body sensor assembly (intake air pressure sensor, intake air temperature sensor, throttle position sensor)
6. FID (fast idle solenoid)
7. Rectifier/regulator
8. Lean angle sensor
9. Starting circuit cut-off relay
10.Turn signal relay
11.Radiator fan motor relay
12.Headlight relay
13.ECU (engine control unit)
14.Fuse box
15.Starter relay
16.Battery
17.Rear brake light switch
18.Sidestand switch
19.Neutral switch
20.Crankshaft position sensor
21.Coolant temperature sensor
22.Speed sensor
23.Radiator fan
24.Horn
- Checking the switches
- Checking the bulbs and bulb sockets
- Checking the fuses
- Checking and charging the battery
- Checking the relays
- Checking the turn signal relay
- Checking the diode
- Checking the spark plug cap
- Checking the ignition coil
- Checking the ignition spark gap
- Checking the crankshaft position sensor
- Checking the lean angle sensor
- Checking the starter motor operation
- Checking the stator coil
- Checking the rectifier/regulator
- Checking the horn
- Checking the fuel sender
- Checking the speed sensor
- Checking the radiator fan motor
- Checking the coolant temperature sensor
- Checking the throttle body sensor assembly
- Checking the fid (fast idle solenoid)
Troubleshooting
If the fuel pump fails to operate.
NOTE:
Before troubleshooting, remove the following part(s):
1. Rider seat
2. Fuel tank
...
Checking the switches
1. Clutch switch
2. Main switch
3. Front brake light switch
4. Sidestand switch
5. Rear brake light switch
6. Neutral switch
7. Turn signal switch
8. Horn switch
9. Dimmer switch
10.Pass ...
Other materials:
Checking the condition of the bulbs
The following procedure applies to all of the
bulbs.
1. Remove:
Bulb
WARNINGSince the headlight bulbs get extremely
hot,
keep flammable products and your hands
away from them until they have cooled
down.
CAUTION:
Be sure to hold the socket firmly when re ...
Checking the crankshaft
1. Measure:
Crankshaft runout
Out of specification Replace
the crankshaft,
bearing or both.
NOTE:
Turn the crankshaft slowly.
2. Measure:
Big end side clearance
Out of specification Replace
the crankshaft.
3. Measure:
Crankshaft width
Out of specification&nbs ...
Checking the fid (fast idle solenoid)
1. Disconnect:
FID (fast idle solenoid) coupler
2. Check:
FID (fast idle solenoid) resistance
a. Disconnect the FID (fast idle solenoid) coupler
from the FID.
b. Connect the pocket tester ( × 10)
to the terminals
of the FID (fast idle solenoid).
Positive tester probe ...