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:
Identification numbers
Record the key identification number,
vehicle identification number and model
label information in the spaces provided
below for assistance when
ordering spare parts from a Yamaha
dealer or for reference in case the vehicle
is stolen.
KEY IDENTIFICATION NUMBER:
VEHICLE IDENTIFICATION ...
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
shown.
Positive tester probe
pink/white "1"
Negative tester probe
gray/black "2"
...
Removing the starter clutch
1. Remove:
Starter clutch bolts "1"
NOTE:
While holding the generator rotor "2" with the
sheave holder "3", remove the starter clutch
bolts.
Do not allow the sheave holder to touch the
projection on the generator rotor.
...