Yamaha YZF-R125 Service Manual: Checking the starter clutch
1. Check:
- Starter clutch rollers "1"
- Starter clutch spring caps "2"
- Starter clutch springs "3"
Damage/wear 
Replace the starter
clutch
assembly.
2. Check:
- Starter clutch idle gear
- Starter clutch gear Burrs/chips/roughness/wear Replace the defective part(s).
3. Check:
- Starter clutch gear contacting surfaces Damage/pitting/wear Replace the starter clutch gear.
4. Check:
- Starter clutch operation
a. Install the starter clutch gear "1" onto the starter clutch and hold the generator rotor.
b. When turning the starter clutch gear clockwise "A", the starter clutch and the starter clutch gear should engage, otherwise the starter clutch is faulty and must be replaced.
c. When turning the starter clutch gear counterclockwise
"B", it should turn freely, otherwise
the starter clutch is faulty and must be replaced.
Removing the starter clutch
1. Remove:
Starter clutch bolts "1"
NOTE:
While holding the generator rotor "2" with the
sheave holder "3", remove the starter clutch
bolts.
Do not allow the sheave holder to touch th ...
Installing the starter clutch
1. Install:
Starter clutch assembly
Starter clutch bolts "1"
NOTE:
While holding the generator rotor "2" with the
sheave holder "3", tighten the starter clutch
bolts.
Do not allow t ...
Other materials:
Checking the drive sprocket
1. Check:
Drive sprocket
More than 1/4 tooth "a" wear
Replace the
drive chain sprockets as a set.
Bent teeth Replace the drive
chain sprockets
as a set.
b. Correct
1. Drive chain roller
2. Drive chain sprocket
Checking the rear wheel sprocket
Refer to "CHECKING AND R ...
Overheating
Engine
1. Clogged coolant passages
Cylinder head and piston
Heavy carbon buildup
2. Engine oil
Incorrect oil level
Incorrect oil viscosity
Inferior oil quality
Cooling system
1. Coolant
Low coolant level
2. Radiator
Damaged or leaking radiator
Faulty radiator cap
...
For your safety - pre-operation checks
Inspect your vehicle each time you use it to make sure the vehicle is in safe
operating condition. Always follow the inspection
and maintenance procedures and schedules described in the Owner's Manual.
WARNING
Failure to inspect or maintain the vehicle properly increases the possibility of
...