Yamaha YZF-R125 Service Manual: 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-inner-rotor-and-outerrotor clearance "c"
Out of specification Replace
the oil pump.
1. Inner rotor
2. Outer rotor
3. Oil pump housing 
3. Check:
Oil pump operation
Rough movement 
Repeat steps (1)
and
(2) or replace the defective part(s).
Oil pump
...
Assembling the oil pump
1. Lubricate:
Oil pump inner rotor
Oil pump outer rotor
Oil pump driven gear
(with the recommended lubricant)
2. Install:
Oil pump outer rotor
Oil pump inner rotor "1"
Oil pump dr ...
Other materials:
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 ...
Air induction system
1. Air induction system hose (air filter case to
reed valve assembly)
2. Air induction system reed valve assembly
3. Air induction system hose (reed valve
assembly to exhaust pipe)
Checking the air induction system
Air injection
The air induction system burns unburned exhaust
gases b ...
Faulty lighting or signaling system
Headlight does not come on
- Wrong headlight bulb
- Too many electrical accessories
- Hard charging
- Incorrect connection
- Improperly grounded circuit
- Poor contacts (main or light switch)
- Burnt-out headlight bulb
Headlight bulb burnt out
- Wrong headlight bulb
- Faulty battery
- Fau ...