Yamaha YZF-R125 Service Manual: Checking the turn signal relay
1. Check:
Turn signal relay input voltage
Out of specification →The wiring circuit
from
the main switch to the turn signal relay coupler
is faulty and must be repaired.
a. Connect the pocket tester (DC 20 V) to the
turn signal relay terminal as shown.
- Positive tester probe 
brown "1"
- Negative tester probe 
ground 
b. Set the main switch to "ON".
c. Measure the turn signal relay input voltage.
2. Check:
Turn signal relay output voltage
Out of specification Replace.
a. Connect the pocket tester (DC 20 V) to the
turn signal relay terminal as shown. 
Positive tester probe
brown/white "1"
Negative tester probe
ground
b. Set the main switch to "ON".
c. Measure the turn signal relay output voltage.
Checking the relays
Check each switch for continuity with the pocket
tester. If the continuity reading is incorrect, replace
the relay.
1. Disconnect the relay from the wire harness.
2. Connect the pocket tester ( ...
Checking the diode
1. Check:
Diode
Out of specification Replace.
NOTE:
The pocket tester or the analog pocket tester
readings are shown in the following table.
a. Disconnect the diode from the wire harness.
...
Other materials:
Removing the front fork legs
The following procedure applies to both of the
front fork legs.
1. Stand the vehicle on a level surface.
WARNINGSecurely support the vehicle so that there
is
no danger of it falling over.
2. Loosen:
Handlebar pinch bolt "1"
Handlebar bolt "2"
Upper bracket ...
Overheating
Engine
1. Clogged coolant passages
Cylinder head and piston
Heavy carbon buildup
2. Engine oil
Incorrect oil level
Incorrect oil viscosity
Inferior oil quality
Cooling system
1. Coolant
Low coolant level
2. Radiator
Damaged or leaking radiator
Faulty radiator cap
...
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 ...