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 oil pump
1. Check:
Oil pump drive gear
Oil pump driven gear
Oil pump housing
Oil pump housing cover
Cracks/damage/wear Replace the
defective
part(s).
2. Measure:
Inner-rotor-to-outer-rotor-tip clearance "a"
Outer-rotor-to-oil-pump-housing clearance
"b"
- Oil-pump-housing-to-inn ...
Engine oil and oil filter element
The engine oil level should be checked
before each ride. In addition, the oil
must be changed and the oil filter element
replaced at the intervals specified
in the periodic maintenance and lubrication
chart.
To check the engine oil level
Place the vehicle on a level surface
and hol ...
Checking the radiator
1. Check:
Radiator fins
obstruction clean.
Apply compressed air to the rear of the radiator.
Damage repair or replace.
NOTE:
Straighten any flattened fins with a thin, flat-head
screwdriver.
2. Check:
Radiator hoses
Cracks/damage Replace.
3. Measure:
Radiator cap ...