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:
Adjusting the engine idling speed
NOTE:
Prior to adjusting the engine idling speed, the air
filter element should be clean, and the engine
should have adequate compression.
1. Start the engine and let it warm up for several
minutes.
2. Remove:
Rider seat
Refer to "GENERAL CHASSIS" on page 4-1.
3. Lift the fuel tank. ...
Checking the crankshaft position sensor
1. Disconnect:
Crankshaft position sensor coupler
(from the wire harness)
2. Check:
Crankshaft position sensor resistance
Out of specification Replace
the crankshaft
position sensor/stator assembly.
a. Connect the pocket tester ( × 100) to the
crankshaft position sensor c ...
Separating the crankcase
1. Remove:
Crankcase bolts
NOTE:
Loosen each bolt 1/4 of a turn at a time, in stages
and in the proper sequence as shown.
A. Right crankcase
B. Left crankcase
2. Turn:
Shift drum segment
NOTE:
Turn the shift drum segment "1" to the position
shown in the illustration. In this ...