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:
Checking the cooling system
1. Remove:
Side covers
Upper side cowlings
Refer to "GENERAL CHASSIS" on page 4-1.
2. Check:
Radiator "1"
Radiator inlet hose "2"
Radiator outlet hose "3"
Coolant reservoir hose "4"
Water pump breather hose "5"
Cracks/damage → Replace.
Refer to "RADIATOR" on page 6-1 ...
Installing the piston and cylinder
1. Install:
Top ring "1"
2nd ring "2"
Oil ring expander "3"
Lower oil ring rail "4"
Upper oil ring rail "5"
NOTE:
Be sure to install the piston rings so that the
manufacturer marks or numbers face up.
2. Install:
Piston "1"
Piston pin "2"
Piston pin clips "3"
NOTE:
...
Removing the throttle body
1. Extract the fuel in the fuel tank through the
fuel tank filler hole with a pump.
2. Disconnect:
Fuel hose
WARNINGCover the fuel hose connections with a
cloth
when disconnecting them. Residual pressure
in the fuel lines could cause fuel to
spurt out when removing the h ...