Yamaha YZF-R125 Service Manual: Troubleshooting

Circuit diagram

4. Main fuse 5. Main switch 9. Battery 17.Engine stop switch 25.ECU (engine control unit) 30.Fuel pump 64.Ignition fuse ...

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 se ...

Other materials:

Troubleshooting method
The engine operation is not normal and the engine trouble warning light comes on. 1. Check: Fault code number a. Check the fault code number displayed on the FI diagnostic tool. b. Identify the faulty system with the fault code. Refer to "Self-Diagnostic Function table". c. Identi ...

Checking the fuel pressure
1. Check: Pressure regulator operation a. Remove the fuel hose connector cover "1" and disconnect the fuel hose "2" from the fuel pump. CAUTION:Although the fuel has been removed from the fuel tank, be careful when removing the fuel hose, since there may be fuel remaining i ...

Checking and replacing the rear wheel sprocket
1. Check: Rear wheel sprocket More than 1/4 tooth "a" wear Replace the rear wheel sprocket. Bent teeth Replace the rear wheel sprocket. b. Correct 1. Drive chain roller 2. Rear wheel sprocket 2. Replace: Rear wheel sprocket a. Remove the self-locking nuts and the ...