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 rear brake hose
    1. Check: Brake hoses "1" Cracks/damage/wear  Replace. 2. Check: Brake hose holder "2" Loose connection Tighten the holder bolt. Loose or open holder Fasten properly. 3. Hold the vehicle upright and apply the rear brake several times. 4. Check: Brake ho ...

    Removing the valves
    The following procedure applies to all of the valves and related components. NOTE: Before removing the internal parts of the cylinder head (e.g., valves, valve springs, valve seats), make sure the valves properly seal. 1. Check: Valve sealing Leakage at the valve seat Check the valve ...

    Checking the timing chain and timing chain guide
    1. Check: Timing chain Damage/stiffness Replace the timing chain and camshaft sprocket as a set. 2. Check: Timing chain guide (intake side) Damage/wear Replace. Checking the oil strainer 1. Check: Oil strainer Damage   Replace. Contaminants Clean with solvent. ...

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