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 front brake master cylinder
1. Check:
Brake master cylinder
Damage/scratches/wear Replace.
Brake fluid delivery passages
(brake master cylinder body)
Obstruction Blow out with
compressed air.
2. Check:
Brake master cylinder reservoir
Cracks/damage Replace the brake
master
cylinder.
Brake maste ...
Checking the rear brake caliper
1. Check:
Brake caliper piston "1"
Rust/scratches/wear Replace the
brake
caliper piston.
Brake caliper cylinder "2"
Scratches/wear Replace the
brake caliper
assembly.
Brake caliper body "3"
Cracks/damage Replace the
brake caliper
assembly.
Brake fluid deli ...
Checking the throttle body joint and air filter case joint
1. Remove:
Right lower side cowling
Left lower side cowling
Refer to "GENERAL CHASSIS" on page 4-1.
2. Check:
Throttle body joint "1"
Air filter case joint "2"
Cracks/damage Replace.
3. Install:
Right lower side cowling
Left lower side cowling
Refer to "GENERAL CHAS ...