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:
Installing the cylinder head
1. Install:
Cylinder head
NOTE:
Pass the timing chain through the timing chain
cavity.
2. Tighten:
Cylinder head bolts "1"
Cylinder head bolts "2"
NOTE:
Lubricate the cylinder head bolts and washers
with engine oil.
Tighten the cylinder head bolts in the proper
tighten ...
Removing the cylinder head
1. Align:
"I" mark "a" on the generator rotor
(with the stationary pointer "b" on the generator
cover)
a. Turn the crankshaft counterclockwise.
b. When the piston is at TDC on the compression
stroke, align the "I" mark "c" on the camshaft
sprocket with the mark "d" on the
cylinder h ...
Replacing the air filter element and cleaning the check hose
The air filter element should be replaced
at the intervals specified in the
periodic maintenance and lubrication
chart. Have a Yamaha dealer replace
the air filter element more frequently if
you are riding in unusually wet or dusty
areas. In addition, the air filter check
hose must be ...