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:

    Checking the brake fluid level
    Front brake Front brake Minimum level mark Rear brake Rear brake Minimum level mark Insufficient brake fluid may allow air to enter the brake system, possibly causing it to become ineffective. Before riding, check that the brake fluid is above the minimum level mark an ...

    Checking the starter motor operation
    1. Check: Starter motor operation Does not operate → Perform the electric starting system troubleshooting, starting with step 4. Refer to "TROUBLESHOOTING" on page 8-9. a. Connect the positive battery terminal "1" and starter motor lead "2" with a jumper lead "3". W ...

    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 ...

    2026 Copyright www.yam-r125.net |