Yamaha YZF-R125 Service Manual: Checking the radiator fan motor
1. Check:
- Radiator fan motor Faulty/rough movement → Replace.
a. Disconnect the radiator fan motor coupler from the wire harness.
b. Connect the battery (DC 12 V) as shown.
- Positive tester probe → blue "1"
- Negative tester probe → black "2"
c. Measure the radiator fan motor movement.
Checking the speed sensor
1. Check:
Speed sensor output voltage
Out of specification → Replace.
a. Connect the pocket tester (DC 20 V) to the
speed sensor coupler (wire harness end) as
shown.
Positive tester pro ...
Checking the coolant temperature sensor
1. Remove:
Coolant temperature sensor
WARNING
Handle the coolant temperature sensor
with special care.
Never subject the coolant temperature sensor
to strong shocks. If t ...
Other materials:
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 amou ...
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:
...
Overheating
Engine
1. Clogged coolant passages
Cylinder head and piston
Heavy carbon buildup
2. Engine oil
Incorrect oil level
Incorrect oil viscosity
Inferior oil quality
Cooling system
1. Coolant
Low coolant level
2. Radiator
Damaged or leaking radiator
Faulty radiator cap
...