Yamaha YZF-R125 Service Manual: Troubleshooting
- Any of the following fail to light: turn signal lights, brake light or indicator lights.
- The horn fails to sound.
- The fuel gauge fails to operate.
- The speedometer fails to operate.
NOTE:
- Before troubleshooting, remove the following part(s):
1. Seats
2. Fuel tank
3. Left upper side cowling
4. Right side panel
5. Left lower side cowling
Circuit diagram
4. Main fuse
5. Main switch
9. Battery
14.Neutral switch
25.ECU (engine control unit)
31.Fuel sender
34.Rear brake light switch
35.Front brake light switch
37.Tail/brake light
38.Rear rig ...
Cooling system
...
Other materials:
Checking the cylinder and piston
1. Check:
Piston wall
Cylinder wall
Vertical scratches Replace the
cylinder,
and replace the piston and piston rings as a
set.
2. Measure:
Piston-to-cylinder clearance
a. Measure cylinder bore "C" with the cylinder
bore gauge.
NOTE:
Measure cylinder bore "C" by takin ...
General maintenance and lubrication chart
TIP
The air filter needs more frequent service if you are riding in
unusually wet or dusty areas.
Hydraulic brake service
Regularly check and, if necessary, correct the brake fluid level.
Every two years change the brake fluid.
Replace the brake hoses every four ye ...
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. Connect the pocket tester ( ×
1) to the stator
coil coupler as shown.
b. Measure the sta ...