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 decompression system
1. Check:
Decompression system
a. Check the decompression system with the
camshaft sprocket and the decompression
cam installed to the camshaft.
b. Check that the decompression lever "1"
moves smoothly.
c. Without operating the decompression lever,
check that the decompression cam " ...
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 ...
Fuel tank cap
Fuel tank cap
Fuel tank cap lock cover
Unlock.
To remove the fuel tank cap
Open the fuel tank cap lock cover.
Insert the key into the lock and turn
it 1/4 turn counterclockwise. The
lock will be released and the fuel
tank cap can be removed.
To install the fuel tank ca ...