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:

    Removing the handlebars
    1. Stand the vehicle on a level surface. WARNINGSecurely support the vehicle so that there is no danger of it falling over. 2. Remove: Handlebar grip "1" NOTE: Blow compressed air between the handlebar and the handlebar grip, and gradually push the grip off the handleb ...

    Bleeding the hydraulic brake system
    WARNINGBleed the hydraulic brake system whenever: the system is disassembled. a brake hose is loosened, disconnected or replaced. the brake fluid level is very low. brake operation is faulty. NOTE: Be careful not to spill any brake fluid or allow th ...

    Starting failures
    Engine 1. Cylinder and cylinder head - Loose spark plug - Loose cylinder head or cylinder - Damaged cylinder head gasket - Damaged cylinder gasket - Worn or damaged cylinder - Incorrect valve clearance - Improperly sealed valve - Incorrect valve-to-valve-seat contact - Incorrect valve timi ...

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