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:
Installing the generator
1. Install:
Woodruff key
Generator rotor
Washer
Generator rotor nut
NOTE:
Clean the tapered portion of the crankshaft and
the generator rotor hub.
When installing the generator rotor, make sure
the woodruff key is properly sealed in the keyway
of the crankshaft.
2. Tighte ...
Checking the thermostat
1. Check:
Thermostat
Does not open at 80.5-83.5 C (176.9-182.3
F) Replace.
a. Suspend the thermostat "1" in a container "2"
filled with water.
b. Slowly heat the water "3".
c. Place a thermometer "4" in the water.
d. While stirring the water, observe the thermostat
and th ...
Checking the horn
1. Check:
Horn resistance
Out of specification Replace.
a. Disconnect the horn connectors from the
horn terminals.
b. Connect the pocket tester ( × 1) to the horn
terminals.
Positive tester probe
horn terminal "1"
Negative tester probe
horn terminal "2"
c. Measure t ...