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 the timing chain and timing chain guide
    1. Check: Timing chain Damage/stiffness Replace the timing chain and camshaft sprocket as a set. 2. Check: Timing chain guide (intake side) Damage/wear Replace. Checking the oil strainer 1. Check: Oil strainer Damage   Replace. Contaminants Clean with solvent. ...

    Checking the relays
    Check each switch for continuity with the pocket tester. If the continuity reading is incorrect, replace the relay. 1. Disconnect the relay from the wire harness. 2. Connect the pocket tester ( × 1) and battery (12 V) to the relay terminal as shown. Check the relay operation. Out ...

    Installing the shift shaft
    1. Install: Stopper lever "1" Stopper lever spring "2" NOTE: Install the stopper lever spring as shown in the illustration. Hook the ends of the stopper lever spring onto the stopper lever and the crankcase boss "3". Mesh the stopper lever with the shift drum segment assembly. ...

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