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 ...

    Other materials:

    Installing the crankshaft
    1. Install: Crankshaft "1" NOTE: Install the crankshaft with the crankshaft installer pot "2", crankshaft installer bolt "3", adapter (M12) "4" and spacer (crankshaft installer) "5". CAUTION:To avoid scratching the crankshaft and to ease the installation procedure, lubricate ...

    Disassembling the front wheel
    1. Remove: Oil seal Wheel bearings a. Clean the surface of the front wheel hub. b. Remove the oil seal "1" with a flat-head screwdriver. NOTE: To prevent damaging the wheel, place a rag "2" between the screwdriver and the wheel surface. c. Remove the wheel bearings "3" with a ge ...

    Checking and lubricating the brake and clutch levers
    Brake lever Brake lever Clutch lever Clutch lever The operation of the brake and clutch levers should be checked before each ride, and the lever pivots should be lubricated if necessary. Recommended lubricants:Brake lever: Silicone grease Clutch lever: Lithium-soap ...

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