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:
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 ...
Troubleshooting
Although Yamaha motorcycles receive
a thorough inspection before shipment
from the factory, trouble may occur during
operation. Any problem in the fuel,
compression, or ignition systems, for
example, can cause poor starting and
loss of power.
The following troubleshooting charts
repre ...
Checking the timing chain tensioner
1. Check:
Timing chain tensioner
Cracks/damage/rough movement Replace.
a. Lightly press the timing chain tensioner rod
into the timing chain tensioner housing by
hand.
NOTE:
While pressing the timing chain tensioner rod,
wind it clockwise with a thin screwdriver "1" until
it stops.
b. ...