Yamaha YZF-R125 Service Manual: Checking the bulbs and bulb sockets
NOTE:
Do not check any of the lights that use LEDs.
Check each bulb and bulb socket for damage or wear, proper connections, and also for continuity between the terminals.
Damage/wear
Repair or replace
the bulb,
bulb socket or both.
Improperly connected 
Properly
connect.
No continuity 
Repair or replace the
bulb, bulb
socket or both.
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 ...
Types of bulbs
The bulbs used on this vehicle are shown in the
illustration.
Bulbs "a" and "b" are used for the headlights
and usually use a bulb holder that must be detached
before removing the bulb. The m ...
Other materials:
Checking the ignition spark gap
1. Check:
Ignition spark gap
Out of specification Perform the
ignition
system troubleshooting, starting with step 5.
Refer to "TROUBLESHOOTING" on page
8-3.
NOTE:
If the ignition spark gap is within specification,
the ignition system circuit is operating normally.
a. Disconnect the spa ...
Periodic maintenance and adjustment
Periodic inspection, adjustment, and lubrication
will keep your vehicle in the
safest and most efficient condition possible.
Safety is an obligation of the vehicle
owner/operator. The most important
points of vehicle inspection, adjustment,
and lubrication are explained on
the followin ...
Checking the front brake caliper
1. Check:
Brake caliper pistons "1"
Rust/scratches/wear Replace the
brake
caliper assembly.
Brake caliper body "2"
Cracks/damage Replace the brake
caliper
assembly.
Brake fluid delivery passages
(brake caliper body)
Obstruction Blow out with
compressed air.
...