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:
Lubricating the drive chain
The drive chain consists of many interacting
parts. If the drive chain is not maintained properly,
it will wear out quickly. Therefore, the drive
chain should be serviced, especially when the
vehicle is used in dusty areas.
This vehicle has a drive chain with small rubber
O-rings between eac ...
Incorrect engine idling speed
Engine
1. Cylinder and cylinder head
Incorrect valve clearance
Damaged valve train components
2. Air filter
Clogged air filter element
Fuel system
1. Throttle body
Damaged or loose throttle body joint
Improperly adjusted engine idling speed (idle
adjusting screw)
Improper ...
Checking the thermostat
1. Check:
Thermostat
Does not open at 80.5-83.5 C (176.9-182.3
F) Replace.
a. Suspend the thermostat "1" in a container "2"
filled with water.
b. Slowly heat the water "3".
c. Place a thermometer "4" in the water.
d. While stirring the water, observe the thermostat
and th ...