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:
Checking the drive sprocket
1. Check:
Drive sprocket
More than 1/4 tooth "a" wear
Replace the
drive chain sprockets as a set.
Bent teeth Replace the drive
chain sprockets
as a set.
b. Correct
1. Drive chain roller
2. Drive chain sprocket
Checking the rear wheel sprocket
Refer to "CHECKING AND R ...
Checking the rectifier/regulator
1. Check:
Rectifier/regulator output voltage
Out of specification → Replace the
rectifier/
regulator.
a. Set the engine tachometer to the spark plug
lead.
b. Connect the pocket tester (DC 20 V) to the
rectifier/regulator coupler as shown.
Positive tester probe
red "1"
Negat ...
Outline of the fi system
The main function of a fuel supply system is to provide fuel to the
combustion chamber at the optimum
air-fuel ratio in accordance with the engine operating conditions and the
atmospheric temperature. In
the conventional carburetor system, the air-fuel ratio of the mixture that is
supplied t ...