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.
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    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:

    Adjusting the clutch cable free play
    1. Check: Clutch cable free play "a" Out of specification Adjust. 2. Adjust: Clutch cable free play a. Pull back the rubber cover "1" b. Loosen the locknut "2". c. Turn the adjusting bolt "3" in direction "a" or "b" until the specified clutch cable free play is obtained. ...

    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 ...

    Installing the front wheel (disc)
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