Yamaha YZF-R125 Service Manual: Checking the rectifier/regulator
1. Check:
Rectifier/regulator output voltage
Out of specification → Replace the
rectifier/
regulator.
a. Set the engine tachometer to the spark plug lead.
b. Connect the pocket tester (DC 20 V) to the
rectifier/regulator coupler as shown.
- Positive tester probe
red "1" - Negative tester probe
black "2"
c. Start the engine and let it run at approximately 5000 r/min.
d. Measure the charging voltage.
Checking the stator coil
1. Disconnect:
Stator coil coupler
(from the wire harness)
2. Check:
Stator coil resistance
Out of specification → Replace the
crankshaft
position sensor/stator assembly.
a. Conne ...
Checking the horn
1. Check:
Horn resistance
Out of specification Replace.
a. Disconnect the horn connectors from the
horn terminals.
b. Connect the pocket tester ( × 1) to the horn
terminals.
Positiv ...
Other materials:
Checking the thermostat
1. Check:
Thermostat
Does not open at 80.5-83.5 C (176.9-182.3
F) Replace.
a. Suspend the thermostat "1" in a container "2"
filled with water.
b. Slowly heat the water "3".
c. Place a thermometer "4" in the water.
d. While stirring the water, observe the thermostat
and th ...
Checking the ignition coil
1. Check:
Primary coil resistance
Out of specification Replace.
a. Disconnect the ignition coil connectors from
the ignition coil terminals.
b. Connect the pocket tester ( × 1)
to the ignition
coil as shown.
Positive tester probe
red/white "1"
Negative tester probe
orange ...
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 ...