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:
Removing the piston
1. Remove:
Piston pin clips "1"
Piston pin "2"
Piston "3"
CAUTION:Do not use a hammer to drive the piston
pin
out.
NOTE:
Before removing the piston pin clip, cover the
crankcase opening with a clean rag to prevent
the piston pin clip from falling in ...
Checking the oil pump
1. Check:
Oil pump drive gear
Oil pump driven gear
Oil pump housing
Oil pump housing cover
Cracks/damage/wear Replace the
defective
part(s).
2. Measure:
Inner-rotor-to-outer-rotor-tip clearance "a"
Outer-rotor-to-oil-pump-housing clearance
"b"
- Oil-pump-housing-to-inn ...
Assembling the crankcase
1. Thoroughly clean all the gasket mating surfaces
and crankcase mating surfaces.
2. Apply:
Sealant
(onto the crankcase mating surfaces)
NOTE:
Do not allow any sealant to come into contact
with the oil gallery.
3. Install:
Right crankcase
NOTE:
Turn the shift drum segment ...