Yamaha YZF-R125 Service Manual: Checking the transmission

Yamaha YZF-R125 Service Manual / Engine / Transmission / Checking the transmission

1. Measure:

  • Main axle runout (with a centering device and dial gauge "1") Out of specification Replace
    the main axle.

Checking the transmission


2. Measure:

  • Drive axle runout (with a centering device and dial gauge "1") Out of specification Replace
    the drive axle.

Checking the transmission


3. Check:

  • Transmission gears Blue discoloration/pitting/wear
    Replace the defective gear(s).
  • Transmission gear dogs Cracks/damage/rounded edges
    Replace the defective gear(s).

Checking the transmission


4. Check:

  • Transmission gear engagement (each pinion gear to its respective wheel gear) Incorrect Reassemble the
    transmission axle assemblies.

5. Check:

  • Transmission gear movement Rough movement Replace the
    defective part(s).
    Checking the shift drum assembly
    1. Check: Shift drum groove Damage/scratches/wear Replace the shift drum assembly. Shift drum segment "1" Damage/wear  Replace the shift drum assembly. Shift drum bearing "2" ...

    Checking the clutch push rods
    1. Check: Long clutch push rod Cracks/damage/wear Replace the long clutch push rod. 2. Measure: Push rod bending limit Out of specification Replace the long clutch push rod. ...

    Other materials:

    Checking the camshaft sprocket and timing chain guide
    1. Check: Camshaft sprocket More than 1/4 tooth wear "a" Replace the camshaft sprocket, timing chain and crankshaft as a set. a. 1/4 tooth b. Correct 1. Timing chain roller 2. Camshaft sprocket 2. Check: Timing chain guide (exhaust side) Damage/wear Replace. ...

    Checking the radiator fan motor
    1. Check: Radiator fan motor Faulty/rough movement → Replace. a. Disconnect the radiator fan motor coupler from the wire harness. b. Connect the battery (DC 12 V) as shown. Positive tester probe → blue "1" Negative tester probe → black "2" c. Measure ...

    Removing the generator
    1. Remove: Generator rotor nut "1" Washer NOTE: While holding the generator rotor "2" with the sheave holder "3", loosen the generator rotor nut. Do not allow the sheave holder to touch the projection on the generator rotor. 2. Remove: Generator rotor "1" (with the ...

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