Yamaha YZF-R125 Service Manual: 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 probe gray "1"
- Negative tester probe gray/black "2"
b. Set the main switch to "ON".
c. Elevate the front wheel and slowly rotate it.
d. Measure the voltage of gray and gray/black.
With each full rotation of the front wheel, the voltage reading should cycle from 0 V to 5.0 V to 0 V to 5.0 V.
Checking the fuel sender
1. Drain the fuel from the fuel tank.
2. Check:
Fuel sender resistance
Out of specification → Replace the fuel
sender.
a. Connect the pocket tester ( ×
10) to the fuel
sender c ...
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.
Posi ...
Other materials:
Removing the primary drive gear and balancer gears
1. Loosen:
Primary drive gear nut "1"
NOTE:
Place the aluminum plate "a" between the balancer
drive gear "2" and the balancer driven
gear "3", and then loosen the primary drive gear
nut.
2. Straighten the lock washer tab.
3. Loosen:
Balancer driven gear nut "1"
NOTE:
Place ...
Replacing a turn signal light bulb
Remove the turn signal light lens
by removing the screw.
Screw
Remove the burnt-out bulb by
pushing it in and turning it counterclockwise.
Insert a new bulb into the socket,
push it in, and then turn it clockwise
until it stops.
Install the lens by installing ...
Self-diagnostic function table
If the ECU detects an abnormal signal from a sensor while the vehicle is
being driven, the ECU illuminates
the engine trouble warning light and provides the engine with alternate
operating instructions that
are appropriate for the type of malfunction.
When an abnormal signal is received fro ...