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 condition of the bulb sockets
The following procedure applies to all of the bulb
sockets.
1. Check:
Bulb socket (for continuity)
(with the pocket tester)
No continuity Replace.
NOTE:
Check each bulb socket for continuity in the
same manner as described in the bulb section,
however, note the following.
a. Install a ...
Checking the rear brake hose
1. Check:
Brake hoses "1"
Cracks/damage/wear
Replace.
2. Check:
Brake hose holder "2"
Loose connection Tighten the
holder bolt.
Loose or open holder Fasten
properly.
3. Hold the vehicle upright and apply the rear
brake several times.
4. Check:
Brake ho ...
Changing the engine oil
1. Remove:
Right bottom cowling
Right upper side cowling
Right lower side cowling
Refer to "GENERAL CHASSIS" on page 4-1.
2. Start the engine, warm it up for several minutes,
and then turn it off.
3. Place a container under the engine oil drain
bolt.
4. Install:
Engine oil d ...