Yamaha YZF-R125 Service Manual: Checking the transmission
1. Measure:
- Main axle runout
(with a centering device and dial gauge "1")
Out of specification
Replace
the main axle.
2. Measure:
- Drive axle runout
(with a centering device and dial gauge "1")
Out of specification
Replace
the drive axle.
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).
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:
Installing the engine
1. Install:
Engine "1"
Engine mounting bolt (rear lower side) "2"
Engine mounting nut (rear lower side) "3"
Engine mounting bolt (rear upper side) "4"
Engine mounting nut (rear upper side) "5"
Engine mounting bolt (front side) "6"
Engine mounting nut (front side) "7"
NOTE:
Do not ...
Checking the rectifier/regulator
1. Check:
Rectifier/regulator output voltage
Out of specification → Replace the
rectifier/
regulator.
a. Set the engine tachometer to the spark plug
lead.
b. Connect the pocket tester (DC 20 V) to the
rectifier/regulator coupler as shown.
Positive tester probe
red "1"
Negat ...
Disassembling the water pump
1. Remove:
Water pump seal "1"
NOTE:
Remove the water pump seal from the inside of
the water pump housing "2".
2. Remove:
Bearing "1"
NOTE:
Remove the bearing from the outside of the water
pump housing "2".
...