Yamaha YZF-R125 Service Manual: Checking the spark plug

1. Remove:

  • Right side cover Refer to "GENERAL CHASSIS" on page 4-1.

2. Disconnect:

  • Spark plug cap

3. Remove:

  • Spark plug
CAUTION:

Before removing the spark plug, blow away any dirt accumulated in the spark plug well with compressed air to prevent it from falling into the cylinder.

4. Check:

Spark plug type Incorrect →Change.


5. Check:

  • Electrode "1" Damage/wear→ Replace the spark plug.
  • Insulator "2" Abnormal color→ Replace the spark plug.

    Normal color is medium-to-light tan.

6. Clean:

  • Spark plug (with a spark plug cleaner or wire brush)

7. Measure:

  • Spark plug gap "a" (with a wire thickness gauge) Out of specification → Regap.

Checking the spark plug


8. Install:

  • Spark plug

NOTE:

Before installing the spark plug, clean the spark plug and gasket surface.

9. Connect:

  • Spark plug cap

10.Install:

  • Right side cover Refer to "GENERAL CHASSIS" on page 4-1.
    Adjusting the throttle cable free play
    NOTE: Prior to adjusting the throttle cable free play, the engine idling speed should be adjusted. 1. Check: Throttle cable free play "a" Out of specification →Adjust. 2. Remov ...

    Checking the ignition timing
    NOTE: Prior to checking the ignition timing, check the wiring connections of the entire ignition system. Make sure all connections are tight and free of corrosion. 1. Remove: Rider seat L ...

    Other materials:

    Operation and important riding points
    Read the Owner's Manual carefully to become familiar with all controls. If there is a control or function you do not understand, ask your Yamaha dealer. WARNING Failure to familiarize yourself with the controls can lead to loss of control, which could cause an accident or injury. TIP ...

    Troubleshooting
    Any of the following fail to light: turn signal lights, brake light or indicator lights. The horn fails to sound. The fuel gauge fails to operate. The speedometer fails to operate. NOTE: Before troubleshooting, remove the following part(s): 1. Seats 2. Fuel tank 3. Left upper ...

    Starting the engine
    In order for the ignition circuit cut-off system to enable starting, one of the following conditions must be met: The transmission is in the neutral position. The transmission is in gear with the clutch lever pulled and the sidestand up. 1. Turn the key to "ON" and make sure ...

    2025 Copyright www.yam-r125.net |