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:
Avoid Carbon Monoxide Poisoning
All engine exhaust contains carbon
monoxide, a deadly gas. Breathing carbon
monoxide can cause headaches,
dizziness, drowsiness, nausea, confusion,
and eventually death.
Carbon Monoxide is a colorless, odorless,
tasteless gas which may be
present even if you do not see or smell
any en ...
Protective apparel
The majority of fatalities from motorcycle
accidents are the result of head injuries.
The use of a safety helmet is the
single most critical factor in the prevention
or reduction of head injuries.
Always wear an approved helmet.
Wear a face shield or goggles.
Wind in your unprotecte ...
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:
...