Yamaha YZF-R125 Service Manual: Checking the relays

Check each switch for continuity with the pocket tester. If the continuity reading is incorrect, replace the relay.


1. Disconnect the relay from the wire harness.

2. Connect the pocket tester ( × 1) and battery (12 V) to the relay terminal as shown.

Check the relay operation.

Out of specification →  Replace.

Starter relay

Starter relay


1. Positive battery terminal

2. Negative battery terminal

3. Positive tester probe

4. Negative tester probe


Starting circuit cut-off relay

Starting circuit cut-off relay


1. Positive battery terminal

2. Negative battery terminal

3. Positive tester probe

4. Negative tester probe


Headlight relay

Headlight relay


1. Positive battery terminal

2. Negative battery terminal

3. Positive tester probe

4. Negative tester probe


Radiator fan motor relay

Radiator fan motor relay


1. Positive battery terminal

2. Negative battery terminal

3. Positive tester probe

4. Negative tester probe


    Checking and charging the battery
    WARNINGBatteries generate explosive hydrogen gas and contain electrolyte which is made of poisonous and highly caustic sulfuric acid. Therefore, always follow these preventive mea ...

    Checking the turn signal relay
    1. Check: Turn signal relay input voltage Out of specification →The wiring circuit from the main switch to the turn signal relay coupler is faulty and must be repaired. a. Connect the poc ...

    Other materials:

    Chassis tightening torques
    NOTE: First, tighten the lower ring nut to approximately 48 Nm (4.8 m.kg, 35 ft.lb) with a torque wrench, then loosen the lower ring nut completely. Retighten the lower ring nut to 13 Nm (1.3 m.kg, 9.4 ft.lb) with a torque wrench. ...

    Checking and lubricating the cables
    The following procedure applies to all of the inner and outer cables. WARNINGDamaged outer cable may cause the cable to corrode and interfere with its movement. Replace damaged outer cable and inner cables as soon as possible. 1. Check: Outer cable Damage Replace. 2 ...

    Checking the rectifier/regulator
    1. Check: Rectifier/regulator output voltage Out of specification → Replace the rectifier/ regulator. a. Set the engine tachometer to the spark plug lead. b. Connect the pocket tester (DC 20 V) to the rectifier/regulator coupler as shown. Positive tester probe red "1" Negat ...

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