2020 YAMAHA YZF-R125 lock

Periodic maintenance and adjustment
6-22
6
EAU36505
Brake light switches
The brake light should come on just
before braking takes effect. The brake
light is activated by switches connect-
ed to the brake lever and brake pedal.
Since the brake light switches are
components of the anti-lock brake sys-
tem, they should only be serviced by a
Yamaha dealer.
EAU22393
Checking the front and rear
brake pads
The front and rear brake pads must be
checked for wear at the intervals spec-
ified in the periodic maintenance and
lubrication chart.
EAU22421Front brake pads
Each front brake pad is provided with a
wear indicator groove, which allows
you to check the brake pad wear with-
out having to disassemble the brake.
To check the brake pad wear, check
the wear indicator groove. If a brake
pad has worn to the point that the wear
indicator groove has almost disap-
peared, have a Yamaha dealer replace
the brake pads as a set.
1. Wear indicator groove
ZAUM1466
1
UB5GE1E0.book Page 22 Monday, August 26, 2019 3:02 PM

Periodic maintenance and adjustment
6-24
6Clean the filler cap before re-
moving. Use only DOT 4 brake
fluid from a sealed container.
Use only the specified brake flu-
id; otherwise, the rubber seals
may deteriorate, causing leak-
age.
Refill with the same type of
brake fluid. Adding a brake fluid
other than DOT 4 may result in a
harmful chemical reaction.
Be careful that water or dust
does not enter the brake fluid
reservoir when refilling. Water
will significantly lower the boil-
ing point of the fluid and may re-
sult in vapor lock, and dirt may
clog the ABS hydraulic unit
valves.
NOTICE
ECA17641
Brake fluid may damage painted
surfaces or plastic parts. Always
clean up spilled fluid immediately.
As the brake pads wear, it is normal for
the brake fluid level to gradually go
down. A low brake fluid level may indi-
cate worn brake pads and/or brake
system leakage; therefore, be sure to
check the brake pads for wear and the
brake system for leakage. If the brake
fluid level goes down suddenly, have a
Yamaha dealer check the cause before
further riding.
EAU22734
Changing the brake fluid
Have a Yamaha dealer change the
brake fluid every 2 years. In addition,
have the seals of the master cylinders
and brake calipers, as well as the brake
hoses replaced at the intervals listed
below or sooner if they are damaged or
leaking.
Brake seals: every 2 years
Brake hoses: every 4 years
UB5GE1E0.book Page 24 Monday, August 26, 2019 3:02 PM

Periodic maintenance and adjustment
6-25
6
EAU22762
Drive chain slack
The drive chain slack should be
checked before each ride and adjusted
if necessary.
EAU74253To check the drive chain slack
1. Place the motorcycle on the side-
stand.
TIP
When checking and adjusting the drive
chain slack, there should be no weight
on the motorcycle.
2. Shift the transmission into the
neutral position.
3. Measure the drive chain slack as
shown.
4. If the drive chain slack is incorrect,
adjust it as follows. NOTICE: Im-
proper drive chain slack will
overload the engine as well as
other vital parts of the motorcy-
cle and can lead to chain slip-
page or breakage. To prevent
this from occurring, keep the
drive chain slack within the
specified limits.
[ECA10572]EAU3431B
To adjust the drive chain slack
Consult a Yamaha dealer before ad-
justing the drive chain slack.
1. Loosen the axle nut and the lock-
nut on each side of the swingarm.
2. To tighten the drive chain, turn the
drive chain slack adjusting bolt on
each side of the swingarm in di-
rection (a). To loosen the drive
chain, turn the adjusting bolt on
each side of the swingarm in di-
rection (b), and then push the rear
wheel forward.
TIP
Using the alignment marks on each
side of the swingarm, make sure that
both drive chain pullers are in the same
position for proper wheel alignment.
3. Tighten the axle nut, then the lock-
nuts to their specified torques.
1. Drive chain slack
Drive chain slack:
30.0–40.0 mm (1.18–1.57 in)
ZAUM1604
1
1. Drive chain slack adjusting bolt
2. Axle nut
3. Alignment marks
4. Locknut
Tightening torques:
Axle nut:
85 N·m (8.5 kgf·m, 63 lb·ft)
Locknut:
15 N·m (1.5 kgf·m, 11 lb·ft)
ZAUM1605
3 21
4
(b) (a)
UB5GE1E0.book Page 25 Monday, August 26, 2019 3:02 PM

Periodic maintenance and adjustment
6-35
6
EAU62590
Replacing a turn signal light
bulb
1. Remove the turn signal light lens
by removing the screw.
2. Remove the turn signal light bulb
socket (together with the bulb) by
turning it counterclockwise.
3. Remove the burnt-out bulb by
pulling it out.
4. Insert a new bulb into the socket.
5. Install the socket (together with
the bulb) by turning it clockwise.
6. Install the turn signal light lens by
installing the screw. NOTICE: Do
not overtighten the screw, oth-
erwise the lens may break.
[ECA11192]EAUM3510
Replacing the license plate
light bulb
1. Remove the license plate light unit
by removing the screw.
2. Remove the license plate light
bulb socket (together with the
bulb) by pulling it out.
3. Remove the burnt-out bulb by
pulling it out.
4. Insert a new bulb into the socket.
5. Install the socket (together with
the bulb) by pushing it in.
6. Install the license plate light unit by
installing the screw.
1. Screw
1. Turn signal light bulb
1
ZAUM1609
1
1. License plate light bulb socket
2. License plate light unit
3. Screw
ZAUM1621
2
3
UB5GE1E0.book Page 35 Monday, August 26, 2019 3:02 PM

Periodic maintenance and adjustment
6-38
6
EAU86430Engine overheating
WARNING
EWAT1041
Do not remove the radiator cap when the engine and radiator are hot.
Scalding hot fluid and steam may be blown out under pressure, which
could cause serious injury. Be sure to wait until the engine has cooled.
Place a thick rag, like a towel, over the radiator cap, and then slowly ro-
tate the cap counterclockwise to the detent to allow any residual pres-
sure to escape. When the hissing sound has stopped, press down on the
cap while turning it counterclockwise, and then remove the cap.
TIP
If coolant is not available, tap water can be temporarily used instead, provided
that it is changed to the recommended coolant as soon as possible.
Wait until the engine
has cooled.
Check the coolant
level in the reservoir
and radiator.Add coolant.
(See TIP.)
The coolant level is
OK.
There is no leakage.
There is leakage.
The coolant level is
low.
Check the cooling
system for leakage.
Have a Yamaha
dealer check and
repair the cooling
system.
Start the engine. If the engine overheats again,
have a Yamaha dealer check and repair the cooling
system.
UB5GE1E0.book Page 38 Monday, August 26, 2019 3:02 PM

10-1
10
Index
A
ABS ...................................................... 3-15
ABS warning light ................................... 3-3
Air filter element and check hose,
replacing and cleaning ....................... 6-14
B
Battery .................................................. 6-31
Brake and clutch levers, checking and
lubricating .......................................... 6-28
Brake and shift pedals, checking and
lubricating .......................................... 6-28
Brake fluid, changing ........................... 6-24
Brake fluid level, checking ................... 6-23
Brake lever ........................................... 3-14
Brake light switches ............................. 6-22
Brake pedal .......................................... 3-14
Brake pedal free play, adjusting........... 6-21
C
Cables, checking and lubricating ......... 6-27
Care ........................................................ 7-1
Catalytic converter ............................... 3-18
Clutch lever .......................................... 3-13
Clutch lever free play, adjusting ........... 6-20
Coolant ................................................. 6-13
Coolant temperature warning light ......... 3-2
Cowlings, removing and installing ......... 6-7
D
Data recording, vehicle .......................... 9-3
Diagnostic connectors ........................... 9-2
Dimmer/Pass switch ............................ 3-12
Drive chain, cleaning and lubricating ... 6-26
Drive chain slack .................................. 6-25
E
Engine break-in ...................................... 5-1
Engine idling speed .............................. 6-15
Engine oil and oil filter element ............ 6-10
Engine overheating............................... 6-38
Engine serial number.............................. 9-1
Engine stop switch ............................... 3-12
Engine trouble warning light................... 3-3
F
Front and rear brake pads, checking ... 6-22
Front brake lever free play, checking ... 6-21
Front fork, checking ............................. 6-30
Fuel....................................................... 3-16
Fuel consumption, tips for reducing ...... 5-5
Fuel tank cap........................................ 3-16
Fuel tank overflow hose ....................... 3-18
Fuses, replacing ................................... 6-33
H
Handlebar switches .............................. 3-12
High beam indicator light........................ 3-2
Horn switch........................................... 3-12
I
Identification numbers ............................ 9-1
Ignition circuit cut-off system ............... 3-21
Indicator lights and warning lights .......... 3-2
L
License plate light bulb, replacing ........ 6-35
M
Main switch/steering lock ....................... 3-1
Maintenance and lubrication, periodic ... 6-4
Maintenance, emission control
system .................................................. 6-3
Matte color, caution ................................ 7-1
Model label ............................................. 9-1
Multi-function meter unit ........................ 3-4
N
Neutral indicator light.............................. 3-2
P
Parking .................................................... 5-6
Part locations .......................................... 2-1
S
Safety information................................... 1-1
Seats ..................................................... 3-19
Shifting .................................................... 5-4
Shift light ................................................. 3-3
Shift pedal............................................. 3-13
Sidestand .............................................. 3-20
Sidestand, checking and lubricating .... 6-29
Spark plug, checking .............................. 6-9
Specifications ......................................... 8-1
Starting the engine.................................. 5-2
Start switch ........................................... 3-12
Steering, checking ................................ 6-30
Storage ................................................... 7-4
Supporting the motorcycle ................... 6-36
Swingarm pivots, lubricating ................ 6-29
T
Tail/brake light ...................................... 6-34
Throttle grip and cable, checking and
lubricating ........................................... 6-27
Throttle grip free play, adjusting ........... 6-15
Tires ...................................................... 6-17
Tool kit .................................................... 6-2
Troubleshooting .................................... 6-36
Troubleshooting chart........................... 6-37
Turn signal indicator light ....................... 3-2
Turn signal light bulb, replacing............ 6-35
UB5GE1E0.book Page 1 Monday, August 26, 2019 3:02 PM