Yamaha YZF-R125 Service Manual: Checking the starter clutch

1. Check:

  • Starter clutch rollers "1"
  • Starter clutch spring caps "2"
  • Starter clutch springs "3"

Damage/wear Replace the starter
clutch assembly.

Checking the starter clutch


2. Check:

  • Starter clutch idle gear
  • Starter clutch gear Burrs/chips/roughness/wear Replace the defective part(s).

3. Check:

  • Starter clutch gear contacting surfaces Damage/pitting/wear Replace the starter clutch gear.

4. Check:

  • Starter clutch operation

a. Install the starter clutch gear "1" onto the starter clutch and hold the generator rotor.

b. When turning the starter clutch gear clockwise "A", the starter clutch and the starter clutch gear should engage, otherwise the starter clutch is faulty and must be replaced.

c. When turning the starter clutch gear counterclockwise "B", it should turn freely, otherwise the starter clutch is faulty and must be replaced.


    Removing the starter clutch
    1. Remove: Starter clutch bolts "1" NOTE: While holding the generator rotor "2" with the sheave holder "3", remove the starter clutch bolts. Do not allow the sheave holder to touch th ...

    Installing the starter clutch
    1. Install: Starter clutch assembly Starter clutch bolts "1" NOTE: While holding the generator rotor "2" with the sheave holder "3", tighten the starter clutch bolts. Do not allow t ...

    Other materials:

    Preparation for removal and disassembly
    1. Before removal and disassembly, remove all dirt, mud, dust and foreign material. 2. Use only the proper tools and cleaning equipment. Refer to "SPECIAL TOOLS" on page 1-8. 3. When disassembling, always keep mated parts together. This includes gears, cylinders, pistons and other part ...

    Checking the speed sensor
    1. Check: Speed sensor output voltage Out of specification → Replace. a. Connect the pocket tester (DC 20 V) to the speed sensor coupler (wire harness end) as shown. Positive tester probe gray "1" Negative tester probe gray/black "2" b. Set the main switch to "ON". c. ...

    Faulty lighting or signaling system
    Headlight does not come on - Wrong headlight bulb - Too many electrical accessories - Hard charging - Incorrect connection - Improperly grounded circuit - Poor contacts (main or light switch) - Burnt-out headlight bulb Headlight bulb burnt out - Wrong headlight bulb - Faulty battery - Fau ...

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