Yamaha YZF-R125 Owners Manual: Ignition circuit cut-off system

The ignition circuit cut-off system (comprising the sidestand switch, clutch switch and neutral switch) has the following functions.

  • It prevents starting when the transmission is in gear and the sidestand is up, but the clutch lever is not pulled.
  • It prevents starting when the transmission is in gear and the clutch lever is pulled, but the sidestand is still down.
  • It cuts the running engine when the transmission is in gear and the sidestand is moved down.

Periodically check the operation of the ignition circuit cut-off system according to the following procedure.


WARNING
If a malfunction is noted, have a Yamaha dealer check the system before riding.

    Sidestand
    The sidestand is located on the left side of the frame. Raise the sidestand or lower it with your foot while holding the vehicle upright. TIP The built-in sidestand switch is part of the ign ...

    For your safety - pre-operation checks
    Inspect your vehicle each time you use it to make sure the vehicle is in safe operating condition. Always follow the inspection and maintenance procedures and schedules described in the Owner's Ma ...

    Other materials:

    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. ...

    Checking the thermostat
    1. Check: Thermostat Does not open at 80.5-83.5 C (176.9-182.3 F)  Replace. a. Suspend the thermostat "1" in a container "2" filled with water. b. Slowly heat the water "3". c. Place a thermometer "4" in the water. d. While stirring the water, observe the thermostat and th ...

    Installing the drive chain
    1. Lubricate: Drive chain Master link 2. Install: Drive sprocket Drive sprocket retainer bolts 3. Install: Master link O-rings Master link plate Master link clip "1" CAUTION: The closed end of the master link clip must face in the direction of drive ch ...

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