Yamaha YZF-R125 Service Manual: Installing the water pump
1. Install:
- Water pump assembly "1"
- O-rings "2"
NOTE:
- Align the projection "a" on the impeller shaft with the slit "b" on the camshaft sprocket bolt.
- Lubricate the O-rings with a thin coat of lithiumsoap- based grease.
2. Fill:
- Cooling system (with the specified amount of the recommended coolant)
Refer to "CHANGING THE COOLANT" on page 3-15.
3. Check:
Cooling system
Leaks 
Repair or replace the faulty
part.
4. Measure:
Radiator cap opening pressure
Below the specified pressure
Replace the
radiator cap.
Refer to "CHECKING THE RADIATOR" on page 6-3.
Assembling the water pump
1. Install:
Water pump seal "1"
(into the water pump housing "2")
CAUTION:Never lubricate the water pump seal
surface
with oil or grease.
NOTE:
Install the water pump ...
Fuel system
...
Other materials:
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 ...
Troubleshooting
Any of the following fail to light: turn signal lights, brake light or
indicator lights.
The horn fails to sound.
The fuel gauge fails to operate.
The speedometer fails to operate.
NOTE:
Before troubleshooting, remove the following part(s):
1. Seats
2. Fuel tank
3. Left upper ...
Installing the valves
The following procedure applies to all of the
valves and related components.
1. Deburr:
Valve stem end
(with an oil stone)
2. Lubricate:
Valve stem "1"
Valve stem seal "2"
(with the recommended lubricant)
3. Install:
Lower spring seat "1"
Valve stem seal "2"
V ...