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:
Tachometer
Tachometer
Tachometer
Tachometer red zone
The electric tachometer allows the rider
to monitor the engine speed and keep it
within the ideal power range.
When the key is turned to "ON", the tachometer
needle will sweep once
across the r/min range and then return
to zero r/min ...
Checking and lubricating the cables
The following procedure applies to all of the inner
and outer cables.
WARNINGDamaged outer cable may cause the cable to
corrode and interfere with its movement. Replace
damaged outer cable and inner cables
as soon as possible.
1. Check:
Outer cable
Damage Replace.
2 ...
Installing the cylinder head
1. Install:
Cylinder head
NOTE:
Pass the timing chain through the timing chain
cavity.
2. Tighten:
Cylinder head bolts "1"
Cylinder head bolts "2"
NOTE:
Lubricate the cylinder head bolts and washers
with engine oil.
Tighten the cylinder head bolts in the proper
tighten ...