Yamaha YZF-R125 Service Manual: Troubleshooting

The ignition system fails to operate (no spark or intermittent spark).

NOTE:

  • Before troubleshooting, remove the following part(s):

1. Seats

2. Fuel tank

3. Right side cover

4. Left side panel

5. Left upper side cowling

Troubleshooting


Troubleshooting


    Circuit diagram
    2. Crankshaft position sensor 4. Main fuse 5. Main switch 8. Sidestand switch 9. Battery 17.Engine stop switch 23.Lean angle sensor 25.ECU (engine control unit) 26.Ignition coil 27.Spark ...

    Electric starting system
    ...

    Other materials:

    Checking and charging the battery
    WARNINGBatteries generate explosive hydrogen gas and contain electrolyte which is made of poisonous and highly caustic sulfuric acid. Therefore, always follow these preventive measures: Wear protective eye gear when handling or working near batteries. Charge batt ...

    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" Negat ...

    Installing the clutch
    1. Install: Conical spring washer "1" NOTE: Install the conical spring washer as shown in the illustration. 2. Install: Clutch housing Thrust washer "1" NOTE: Be sure to install the thrust washer so that its sharp edge "a" is facing away from the clutch boss. 3. Instal ...

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