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 clutch boss
1. Check:
Clutch boss splines
Damage/pitting/wear Replace the
clutch
boss.
NOTE:
Pitting on the clutch boss splines will cause erratic
clutch operation.
Checking the pressure plate
1. Check:
Pressure plate
Cracks/damage Replace.
Checking the clutch push lever and short clutch push ...
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. ...
Air induction system
1. Air induction system hose (air filter case to
reed valve assembly)
2. Air induction system reed valve assembly
3. Air induction system hose (reed valve
assembly to exhaust pipe)
Checking the air induction system
Air injection
The air induction system burns unburned exhaust
gases b ...