Yamaha YZF-R125 Service Manual: Checking the valve springs

The following procedure applies to all of the valve springs.

1. Measure:

  • Valve spring free length "a" Out of specification Replace the valve spring.

Checking the valve springs


2. Measure:

  • Compressed valve spring force "a" Out of specification Replace the valve spring.

Checking the valve springs


b. Installed length

3. Measure:

  • Valve spring tilt "a" Out of specification Replace the
    valve spring.

Checking the valve springs


    Checking the valve seats
    The following procedure applies to all of the valves and valve seats. 1. Eliminate: Carbon deposits (from the valve face and valve seat) 2. Check: Valve seat Pitting/wear Replace the ...

    Installing the valves
    The following procedure applies to all of the valves and related components. 1. Deburr: Valve stem end (with an oil stone) 2. Lubricate: Valve stem "1" Valve stem seal "2" (with ...

    Other materials:

    Checking the brake fluid level
    Front brake Front brake Minimum level mark Rear brake Rear brake Minimum level mark Insufficient brake fluid may allow air to enter the brake system, possibly causing it to become ineffective. Before riding, check that the brake fluid is above the minimum level mark an ...

    Installing the steering head
    1. Lubricate: Upper bearing Lower bearing Bearing races 2. Install: Lower ring nut Rubber washer Upper ring nut Lock washer Refer to "CHECKING AND ADJUSTING THE STEERING HEAD" on page 3-22. 3. Install: Upper bracket Steering stem nut NOTE: Temporarily tighten t ...

    Supporting the motorcycle
    Since this model is not equipped with a centerstand, follow these precautions when removing the front and rear wheel or performing other maintenance requiring the motorcycle to stand upright. Check that the motorcycle is in a stable and level position before starting any maintenance. A ...

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