Yamaha YZF-R125 Service Manual: Checking the crankshaft position sensor

Yamaha YZF-R125 Service Manual / Electrical system / Electrical components / Checking the crankshaft position sensor

1. Disconnect:

  • Crankshaft position sensor coupler (from the wire harness)

2. Check:

Crankshaft position sensor resistance Out of specification  Replace
the crankshaft position sensor/stator assembly.


a. Connect the pocket tester ( × 100) to the crankshaft position sensor coupler as shown.


  • Positive tester probe
    red "1"
  • Negative tester probe
    white "2"

b. Measure the crankshaft position sensor resistance.

    Checking the ignition spark gap
    1. Check: Ignition spark gap Out of specification Perform the ignition system troubleshooting, starting with step 5. Refer to "TROUBLESHOOTING" on page 8-3. NOTE: If the ignition spark gap ...

    Checking the lean angle sensor
    1. Remove: Lean angle sensor 2. Check: Lean angle sensor output voltage Out of specification Replace. a. Connect the lean angle sensor to the wire harness. b. Connect the pocket tester ...

    Other materials:

    Changing the engine oil
    1. Remove: Right bottom cowling Right upper side cowling Right lower side cowling Refer to "GENERAL CHASSIS" on page 4-1. 2. Start the engine, warm it up for several minutes, and then turn it off. 3. Place a container under the engine oil drain bolt. 4. Install: Engine oil d ...

    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 switch 11.Engine stop switch 12.Start switch Check each switch for continuity with the pocket tes ...

    Checking the speed sensor
    1. Check: Speed sensor output voltage Out of specification → Replace. a. Connect the pocket tester (DC 20 V) to the speed sensor coupler (wire harness end) as shown. Positive tester probe gray "1" Negative tester probe gray/black "2" b. Set the main switch to "ON". c. ...

    2026 Copyright www.yam-r125.net |