Yamaha YZF-R125 Service Manual: Checking the starter motor

Yamaha YZF-R125 Service Manual / Engine / Electric starter / Checking the starter motor

1. Check:

  • Commutator Dirt Clean with 600 grit
    sandpaper.

2. Measure:

  • Commutator diameter "a" Out of specification Replace
    the starter motor.

Checking the starter motor


3. Measure:

  • Mica undercut "a" Out of specification Scrape
    the mica to the proper measurement with a hacksaw blade that has been grounded to fit the commutator.

NOTE:

The mica of the commutator must be undercut to ensure proper operation of the commutator.


4. Measure:

  • Armature assembly resistances (commutator and insulation) Out of specification Replace
    the starter motor.

a. Measure the armature assembly resistances with the pocket tester.


b. If any resistance is out of specification, replace the starter motor.

Checking the starter motor


5. Measure:

  • Brush length "a" Out of specification Replace
    the starter motor front cover/brush holder set.

Checking the starter motor


6. Measure:

  • Brush spring force Out of specification Replace
    the brush springs as a set.

7. Check:

Gear teeth Damage/wear  Replace the gear.


8. Check:

  • Bearing
  • Oil seal
  • Damage/wear Replace the
    starter motor front cover/brush holder set.
    Electric starter
    ...

    Assembling the starter motor
    1. Install: Starter motor front cover/brush holder set "1" Starter motor yoke "2" NOTE: Align the marks "a" on the starter motor yoke and starter motor front cover/brush holder set. ...

    Other materials:

    Checking the drive chain
    1. Measure: 15-link section "a" of the drive chain Out of specification Replace the drive chain. a. Measure the length "a" between the inner sides of the pins and the length "b" between the outer sides of the pins on a 15-link section of the drive chain as shown in the illustration. ...

    Adjusting the drive chain slack
    NOTE: The drive chain slack must be checked at the tightest point on the chain. CAUTION:A drive chain that is too tight will overload the engine and other vital parts, and one that is too loose can skip and damage the swingarm or cause an accident. Therefore, keep the drive ...

    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 ...

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