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:
Changing the engine oil
1. Remove:
Right bottom cowling
Right upper side cowling
Right lower side cowling
Refer to "GENERAL CHASSIS" on page 4-1.
2. Start the engine, warm it up for several minutes,
and then turn it off.
3. Place a container under the engine oil drain
bolt.
4. Install:
Engine oil d ...
Installing the valves
The following procedure applies to all of the
valves and related components.
1. Deburr:
Valve stem end
(with an oil stone)
2. Lubricate:
Valve stem "1"
Valve stem seal "2"
(with the recommended lubricant)
3. Install:
Lower spring seat "1"
Valve stem seal "2"
V ...
Separating the crankcase
1. Remove:
Crankcase bolts
NOTE:
Loosen each bolt 1/4 of a turn at a time, in stages
and in the proper sequence as shown.
A. Right crankcase
B. Left crankcase
2. Turn:
Shift drum segment
NOTE:
Turn the shift drum segment "1" to the position
shown in the illustration. In this ...