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:
Checking and adjusting the steering head
1. Stand the vehicle on a level surface
WARNINGSecurely support the vehicle so that there
is
no danger of it falling over.
NOTE:
Place the vehicle on a suitable stand so that the
front wheel is elevated.
2. Check:
Steering head
Grasp the bottom of the front fork legs an ...
Disassembling the rear brake caliper
1. Remove:
Brake caliper piston "1"
Brake caliper piston dust seal "2"
Brake caliper piston seal "3"
a. Blow compressed air into the brake hose joint
opening "a" to force out the piston from the
brake caliper.
WARNING
Cover the brake caliper piston with a rag.
Be careful no ...
Checking the camshaft
1. Check:
Camshaft lobes
Blue discoloration/pitting/scratches
Replace
the camshaft.
2. Measure:
Camshaft lobe dimensions "a" and "b"
Out of specification Replace
the camshaft.
3. Check:
Camshaft oil passage
Obstruction Blow out with
compressed air. ...