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 condition of the bulbs
The following procedure applies to all of the
bulbs.
1. Remove:
Bulb
WARNINGSince the headlight bulbs get extremely
hot,
keep flammable products and your hands
away from them until they have cooled
down.
CAUTION:
Be sure to hold the socket firmly when re ...
General chassis
Installing the air filter case
1. Install:
Air filter case joint clamp
NOTE:
Align the projection "a" on the air filter case with
the slot "b" in the air filter case joint clamp.
...
Checking the valves and valve guides
The following procedure applies to all of the
valves and valve guides.
1. Measure:
Valve-stem-to-valve-guide clearance
Out of specification Replace the
valve
guide.
Valve-stem-to-valve-guide clearance =
Valve guide inside diameter "a" -
Valve stem diameter "b"
2. Replace:
...