Yamaha YZF-R125 Service Manual: Checking the condition of the bulb sockets
The following procedure applies to all of the bulb sockets.
1. Check:
Bulb socket (for continuity)
(with the pocket tester)
No continuity 
Replace.
NOTE:
Check each bulb socket for continuity in the same manner as described in the bulb section, however, note the following.
a. Install a good bulb into the bulb socket.
b. Connect the pocket tester probes to the respective leads of the bulb socket.
c. Check the bulb socket for continuity. If any of the readings indicate no continuity, replace the bulb socket.
Checking the condition of the bulbs
The following procedure applies to all of the
bulbs.
1. Remove:
Bulb
WARNINGSince the headlight bulbs get extremely
hot,
keep flammable products and your hands
away from them ...
Checking the fuses
The following procedure applies to all of the fuses.
CAUTION:To avoid a short circuit, always turn the
main
switch to "OFF" when checking or replacing
a fuse.
1. Remove:
Ri ...
Other materials:
Checking the shift forks
The following procedure applies to all of the shift
forks.
1. Check:
Shift fork cam follower "1"
Shift fork pawl "2"
Bends/damage/scoring/wear
Replace the
shift fork.
2. Check:
Shift fork guide bar
Roll the shift fork guide bar on a flat surface.
Bends Replace. ...
Checking the switches
1. Clutch switch
2. Main switch
3. Front brake light switch
4. Sidestand switch
5. Rear brake light switch
6. Neutral switch
7. Turn signal switch
8. Horn switch
9. Dimmer switch
10.Pass switch
11.Engine stop switch
12.Start switch
Check each switch for continuity with the pocket tes ...
Troubleshooting
Although Yamaha motorcycles receive
a thorough inspection before shipment
from the factory, trouble may occur during
operation. Any problem in the fuel,
compression, or ignition systems, for
example, can cause poor starting and
loss of power.
The following troubleshooting charts
repre ...