Yamaha YZF-R125 Service Manual: Checking the fuel sender

1. Drain the fuel from the fuel tank.

2. Check:

Fuel sender resistance Out of specification → Replace the fuel sender.


a. Connect the pocket tester ( ×
10) to the fuel sender coupler as shown.


  • Positive tester probe
    sky blue "1"
  • Negative tester probe
    orange/white "2"

Checking the fuel sender


A. Full fuel tank position

B. Empty fuel tank position

b. Measure the fuel sender resistance.

    Checking the horn
    1. Check: Horn resistance Out of specification Replace. a. Disconnect the horn connectors from the horn terminals. b. Connect the pocket tester ( × 1) to the horn terminals. Positiv ...

    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 pro ...

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