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:
Rear wheel
To remove the rear wheel
WARNING
To avoid injury, securely support the
vehicle so there is no danger of it
falling over.
Loosen the axle nut.
Axle nut
Drive chain slack adjusting bolt
Locknut
Brake caliper
Lift the rear wheel off the ground
according to the pr ...
Fuel
Make sure there is sufficient gasoline in
the tank.
WARNING
Gasoline and gasoline vapors are
extremely flammable. To avoid fires
and explosions and to reduce the
risk of injury when refueling, follow
these instructions.
Before refueling, turn off the engine
and be sure that no on ...
Faulty clutch
Clutch slips
1. Clutch
Improperly assembled clutch
Improperly adjusted clutch cable
Loose or fatigued clutch spring
Worn friction plate
Worn clutch plate
2. Engine oil
Incorrect oil level
Incorrect oil viscosity (low)
Deteriorated oil
Clutch drags
1. Clutch
Unevenly t ...