Yamaha YZF-R125 Service Manual: Checking the rocker arms and rocker arm shafts

Yamaha YZF-R125 Service Manual / Engine / Camshaft / Checking the rocker arms and rocker arm shafts

The following procedure applies to all of the rocker arms and rocker arm shafts.

1. Check:

  • Rocker arm Damage/wear Replace.

2. Check:

  • Rocker arm shaft Blue discoloration/excessive wear/pitting/ scratches  Replace or
    check the lubrication system.

3. Measure:

  • Rocker arm inside diameter "a" Out of specification Replace.

Checking the rocker arms and rocker arm shafts


4. Measure:

  • Rocker arm shaft outside diameter "a" Out of specification Replace.

Checking the rocker arms and rocker arm shafts


5. Calculate:

  • Rocker-arm-to-rocker-arm-shaft clearance

NOTE:

Calculate the clearance by subtracting the rocker arm shaft outside diameter from the rocker arm inside diameter.

Out of specification Replace the
defective part(s).


    Checking the camshaft
    1. Check: Camshaft lobes Blue discoloration/pitting/scratches  Replace the camshaft. 2. Measure: Camshaft lobe dimensions "a" and "b" Out of specification Replace the cams ...

    Installing the camshaft and rocker arms
    1. Lubricate: Rocker arms Rocker arm shafts 2. Lubricate: Camshaft 3. Install: Camshaft "1" NOTE: Make sure that the camshaft projections "a" and hole "b" are positioned as s ...

    Other materials:

    Aftermarket Parts, Accessories, and Modifications
    While you may find aftermarket products similar in design and quality to genuine Yamaha accessories, recognize that some aftermarket accessories or modifications are not suitable because of potential safety hazards to you or others. Installing aftermarket products or having other modif ...

    Checking the spark plug
    The spark plug is an important engine component, which is easy to check. Since heat and deposits will cause any spark plug to slowly erode, the spark plug should be removed and checked in accordance with the periodic maintenance and lubrication chart. In addition, the condition of the ...

    Catalytic converters
    This vehicle is equipped with catalytic converters in the exhaust system. WARNING The exhaust system is hot after operation. To prevent a fire hazard or burns: Do not park the vehicle near possible fire hazards such as grass or other materials that easily burn. Park the vehic ...

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