Yamaha YZF-R125 Service Manual: Intake air pressure sensor

1. Check:

  • Intake air pressure sensor output voltage Out of specification Replace the throttle body.

a. Connect the pocket tester (DC 20 V) to the throttle body sensor assembly coupler as shown.


  • Positive tester probe
    pink/white "1"
  • Negative tester probe
    gray/black "2"

Intake air pressure sensor


b. Set the main switch to "ON".

c. Measure the intake air pressure sensor output voltage.

    Throttle position sensor
    1. Check: Throttle position sensor a. Connect the digital circuit tester to the terminals of the throttle body sensor assembly coupler as shown. Positive tester probe → gray/red t ...

    Intake air temperature sensor
    1. Check: Intake air temperature sensor resistance Out of specification Replace the throttle body. a. Connect the pocket tester ( × 1k) to the throttle body sensor assembly co ...

    Other materials:

    Checking and lubricating the sidestand
    Checking and lubricating the sidestand The operation of the sidestand should be checked before each ride, and the sidestand pivot and metal-to-metal contact surfaces should be lubricated if necessary. WARNING If the sidestand does not move up and down smoothly, have a Yamaha deal ...

    Assembling the oil pump
    1. Lubricate: Oil pump inner rotor Oil pump outer rotor Oil pump driven gear (with the recommended lubricant) 2. Install: Oil pump outer rotor Oil pump inner rotor "1" Oil pump driven gear Pin "2" NOTE: When installing the inner rotor, align the pin "2" in the oil pump sh ...

    Installing the radiator
    1. Fill: Cooling system (with the specified amount of the recommended coolant) Refer to "CHANGING THE COOLANT" on page 3-15. 2. Check: Cooling system Leaks Repair or replace any faulty part. 3. Measure: Radiator cap opening pressure Below the specified pressure Repla ...

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