Yamaha YZF-R125 Service Manual: Throttle position sensor
1. Check:
- Throttle position sensor
a. Connect the digital circuit tester to the terminals
of the throttle body sensor assembly
coupler as shown.
- Positive tester probe → gray/red terminal "1"
- Negative tester probe → gray/black terminal "2"
b. Measure the throttle position sensor input voltage.
Out of specification → Replace or repair the
wire harness.
c. Connect the digital circuit tester to the terminals of the throttle body sensor assembly coupler as shown.
- Positive tester probe → yellow terminal "3"
- Negative tester probe → gray/black terminal "2"
d. While slowly opening the throttle, check that the throttle position sensor output voltage is increased.
Voltage does not change or it changes abruptly → Replace the throttle body.
Out of specification (closed position) →
Replace
the throttle body.
Checking the throttle body sensor assembly
WARNING
Do not remove the throttle body sensor assembly.
Handle the throttle body sensor assembly
with special care
Never subject the throttle body sensor assembly
to strong ...
Intake air pressure sensor
1. Check:
Intake air pressure sensor output voltage
Out of specification Replace the throttle
body.
a. Connect the pocket tester (DC 20 V) to the
throttle body sensor assembly coupler as
...
Other materials:
General chassis
Installing the air filter case
1. Install:
Air filter case joint clamp
NOTE:
Align the projection "a" on the air filter case with
the slot "b" in the air filter case joint clamp.
...
Checking the fuel pressure
1. Check:
Pressure regulator operation
a. Remove the fuel hose connector cover "1"
and disconnect the fuel hose "2" from the fuel
pump.
CAUTION:Although the fuel has been removed from
the fuel tank, be careful when removing the
fuel hose, since there may be fuel remaining
i ...
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:
...