Yamaha YZF-R125 Service Manual: Removing the swingarm
1. Stand the vehicle on a level surface.
| WARNING Securely support the vehicle so that there is no danger of it falling over. |
NOTE:
Place the vehicle on a suitable stand so that the rear wheel is elevated.
2. Measure:
- Swingarm side play
- Swingarm vertical movement
a. Measure the tightening torque of the pivot
shaft nut. 
b. Measure the swingarm side play "A" by moving the swingarm from side to side.
c. If the swingarm side play is out of specification,
check the spacers, bearings, and dust
covers. 
3. Remove:
- Pivot shaft nut
- Pivot shaft
- Swingarm "1"
- Swingarm adjusting collar "2"
a. Loosen the pivot shaft nut.
b. Fully turn in the swingarm adjusting collar so that it contacts the frame "3".
c. Remove the pivot shaft nut, washer, pivot shaft and swingarm.
Swingarm
...
Checking the swingarm
1. Check:
Swingarm
Bends/cracks/damage
Replace.
2. Check:
Pivot shaft
Roll the pivot shaft on a flat surface.
Bends Replace.
WARNINGDo not attempt to straighten ...
Other materials:
Faulty clutch
Clutch slips
1. Clutch
Improperly assembled clutch
Improperly adjusted clutch cable
Loose or fatigued clutch spring
Worn friction plate
Worn clutch plate
2. Engine oil
Incorrect oil level
Incorrect oil viscosity (low)
Deteriorated oil
Clutch drags
1. Clutch
Unevenly t ...
Circuit diagram
4. Main fuse
5. Main switch
9. Battery
25.ECU (engine control unit)
36.License plate light
37.Tail/brake light
44.Headlight relay
46.Pass switch
47.Dimmer switch
51.Headlight (low beam)
52.Auxiliary light
54.Headlight (high beam)
58.Meter light
60.High beam indicator light
64.Ignit ...
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 ...