Yamaha YZF-R125 Service Manual: Installing the shift forks and shift drum assembly
1. Install:
- Shift fork-L "1"
- Shift fork-C "2"
- Shift fork-R "3"
- Shift drum assembly "4"
- Springs
- Shift fork guide bar "5"
NOTE:
The embossed marks on the shift forks should face towards the right side of the engine and be in the following sequence: "R", "C", "L".
2. Check:
Transmission
Rough movement 
Repair.
NOTE:
- Apply engine oil to each gear and bearing thoroughly.
- Before assembling the crankcase, make sure that the transmission is in neutral and that the gears turn freely.
Assembling the main axle and drive axle
1. Install:
Toothed washer "1"
Circlip "2"
NOTE:
Be sure to install the circlip so that its sharp
edge "a" is facing away from the toothed washer
and gear.
Be sure the circlip ends ...
Cooling system
...
Other materials:
Checking the rear brake disc
1. Remove:
Rear wheel
Refer to "REAR WHEEL" on page 4-12.
2. Check:
Brake disc
Damage/galling → Replace.
3. Measure:
Brake disc deflection
Out of specification → Correct the brake
disc
deflection or replace the brake disc.
Refer to "CHECKING THE FRONT BRAKE
DIS ...
Checking the rear shock absorber assembly
1. Check:
Rear shock absorber rod
Bends/damage Replace the rear
shock
absorber assembly.
Rear shock absorber
Oil leaks Replace the rear
shock absorber
assembly.
Spring
Damage/wear Replace the
rear shock absorber
assembly.
Bushing
Damage/wear Replace the rea ...
Troubleshooting
Any of the following fail to light: headlight, high beam indicator light,
taillight, license plate light, auxiliary
light or meter light.
NOTE:
Before troubleshooting, remove the following part(s):
1. Seats
2. Fuel tank
...