Yamaha YZF-R125 Service Manual: Charging system
Troubleshooting
The starter motor fails to turn.
NOTE:
Before troubleshooting, remove the following part(s):
1. Seats
2. Fuel tank
3. Left lower side cowling
4. Left upper side cowling
...
Circuit diagram
1. AC magneto
3. Rectifier/regulator
4. Main fuse
9. Battery ...
Other materials:
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 ...
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. ...
Preparation for removal and disassembly
1. Before removal and disassembly, remove all
dirt, mud, dust and foreign material.
2. Use only the proper tools and cleaning equipment.
Refer to "SPECIAL TOOLS" on page 1-8.
3. When disassembling, always keep mated
parts together. This includes gears, cylinders,
pistons and other part ...