2021 YAMAHA YZF-R125 Rear brake

Table of contentsSafety information ............................ 1-1
Description ....................................... 2-1
Left view ......................................... 2-1
Right view ....................................... 2-2
Controls and instruments ............... 2-3
Instrument an d control functions ... 3-1
Main switch/steering lock............... 3-1
Indicator lights and warning lights............................................ 3-2
Multi-function meter unit ................ 3-4
Handlebar switches ...................... 3-12
Clutch lever .................................. 3-13
Shift pedal .................................... 3-14
Brake lever.................................... 3-14
Brake pedal .................................. 3-14
ABS .............................................. 3-15
Fuel tank cap ................................ 3-16
Fuel ............................................... 3-16
Fuel tank breather hose and overflow hose ............................ 3-18
Catalytic converter ....................... 3-19
Seats ............................................ 3-19
Sidestand ..................................... 3-20
Ignition circuit cut-off system ....... 3-21 For your safety – pre-operation
checks
............................................... 4-1
Operation an d important ri din g
points ................................................. 5-1
Engine break-in ............................... 5-1
Starting the engine .......................... 5-2
Shifting ............................................ 5-3
Tips for reducing fuel consumption ................................ 5-4
Parking ............................................ 5-4
Perio dic maintenance an d
a d justment ........................................ 6-1
Tool kit ............................................ 6-2
Periodic maintenance chart for the emission control system .............. 6-3
General maintenance and lubrication chart ........................... 6-4
Removing and installing cowlings... 6-8
Checking the spark plug ................. 6-9
Canister ......................................... 6-10
Engine oil and oil filter element ..... 6-11
Why Yamalube .............................. 6-13
Coolant.......................................... 6-14
Replacing the air filter element
and cleaning the check hose..... 6-15
Adjusting the engine idling speed ......................................... 6-16
Adjusting the throttle grip free play ............................................ 6-16 Valve clearance............................. 6-17
Tires .............................................. 6-17
Cast wheels .................................. 6-19
Adjusting the clutch lever free
play ............................................ 6-20
Checking the front brake lever free play..................................... 6-21
Adjusting the brake pedal free
play ............................................ 6-21
Brake light switches ..................... 6-22
Checking the front and rear brake pads .......................................... 6-22
Checking the brake fluid level ...... 6-23
Changing the brake fluid .............. 6-24
Drive chain slack........................... 6-25
Cleaning and lubricating the drive chain.......................................... 6-26
Checking and lubricating the cables ........................................ 6-27
Checking and lubricating the
throttle grip and cable ............... 6-27
Checking and lubricating the brake and shift pedals............... 6-27
Checking and lubricating the brake and clutch levers ............. 6-28
Checking and lubricating the
sidestand................................... 6-29
Lubricating the rear suspension ... 6-29
Checking the front fork ................. 6-29
Checking the steering................... 6-30
Checking the wheel bearings ....... 6-30UB5GE2E0.book Page 1 Thursday, July 30, 2020 3:08 PM

Description
2-2
2
EAU10421
Right view
2
1
4
76
3
5
1. Rear turn signal lights (page 6-33)
2. Seat lock (page 3-19)
3. Front turn signal light (page 6-33)
4. Engine oil filter element (page 6-11)
5. Dipstick (page 6-11)
6. Brake pedal (page 3-14)
7. Rear brake fluid reservoir (page 6-23)UB5GE2E0.book Page 2 Thursday, July 30, 2020 3:08 PM

Instrument and control functions
3-3
3
EAU88330
Malfunction in dicator li ght
(MIL) “ ”
This light comes on or flashes if a prob-
lem is detected in the engine or other
vehicle control system. If this occurs,
have a Yamaha dealer check the on-
board diagnostic system. The electri-
cal circuit of the warning light can be
checked by vehicle power on. The light
should come on for a few seconds,
and then go off. If the light does not
come on initially when the vehicle pow-
er on, or if the light remains on, have a
Yamaha dealer check the vehicle.NOTICE
ECA26820
If the MIL starts flashin g, re duce en-
g ine speed to prevent exhaust sys-
tem damag e.TIPThe engine is sensitively controlled for
the on-board diagnostic system to de-
tect deterioration and malfunction of
the emission control system. Due to
this specification, the MIL may come
on or flash for vehicle modifications,
lack of maintenance, or excessive or improper use of the motorcycle. To
prevent this, observe these precau-
tions.
 Do not attempt to modify the soft-
ware of the engine control unit.
 Do not add any electrical acces-
sories that interfere with engine
control.
 Do not use aftermarket accesso-
ries or parts such as suspension,
spark plugs, injectors, exhaust
system, etc.
 Do not change drivetrain specifi-
cations (chain, sprockets, wheels,
tires, etc.).
 Do not remove or alter the O2 sen-
sor, air induction system, or ex-
haust parts (catalysts or EXUP,
etc.).
 Maintain proper drive chain.
 Maintain correct tire pressure.
 Maintain proper brake pedal
height to prevent rear brake from
dragging.
 Do not operate the vehicle in an
extreme manner. For example, re-
peated or excessive opening and closing of the throttle, racing,
burnouts, wheelies, extended
half-clutch use, etc.
EAU69895
ABS warnin
g li ght “ ”
This warning light comes on when the
vehicle is first turned on, and goes off
after starting riding. If the warning light
comes on while riding, the anti-lock
brake system may not work correctly.
WARNING
EWA16043
If the ABS warnin g li ght does not
turn off after reachin g 10 km/h (6
mi/h), or if the warnin g li ght comes
on while ri din g:
 Use extra caution to avoi d pos-
si ble wheel lock d uring emer-
g ency brakin g.
 Have a Yamaha dealer check
the vehicle as soon as possi ble.
EAU80372
Shift li ght
This light can be set to come on and go
off at select engine speeds. (See page
3-10.)
ABS
UB5GE2E0.book Page 3 Thursday, July 30, 2020 3:08 PM

Instrument and control functions
3-14
3
EAU12876
Shift pe dalThe shift pedal is located on the left
side of the motorcycle. To shift the
transmission to a higher gear, move
the shift pedal up. To shift the trans-
mission to a lower gear, move the shift
pedal down. (See page 5-3.)
EAU12892
Brake leverThe brake lever is located on the right
side of the handlebar. To apply the
front brake, pull the lever toward the
throttle grip.
EAU12944
Brake pe dalThe brake pedal is located on the right
side of the motorcycle. To apply the
rear brake, press down on the brake
pedal.
1. Shift pedalZAUM1586
1
1. Brake leverZAUM1587
1
1. Brake pedalZAUM1588
1
UB5GE2E0.book Page 14 Thursday, July 30, 2020 3:08 PM

Instrument and control functions
3-15
3
EAU63040
ABSThe Yamaha ABS (Anti-lock Brake
System) features a dual electronic con-
trol system, which acts on the front and
rear brakes independently.
Operate the brakes with ABS as you
would conventional brakes. If the ABS
is activated, a pulsating sensation may
be felt at the brake lever or brake ped-
al. In this situation, continue to apply
the brakes and let the ABS work; do
not “pump” the brakes as this will re-
duce braking effectiveness.
WARNING
EWA16051
Always keep a sufficient d istance
from the vehicle ahea d to match the
ri din g speed even with ABS.
 The ABS performs best with
lon g b rakin g d istances.
 On certain surfaces, such as
rou gh or g ravel roa ds, the b rak-
in g d istance may b e longer with
the ABS than without.The ABS is monitored by an ECU,
which will revert the system to conven-
tional braking if a malfunction occurs.
TIP The ABS performs a self-diagno-
sis test each time the vehicle first
starts off after the key is turned to
“ON” and the vehicle has traveled
at a speed of 10 km/h (6 mi/h) or
higher. During this test, a “click-
ing” noise can be heard from the
hydraulic control unit, and if the
brake lever or brake pedal is even
slightly applied, a vibration can be
felt at the lever and pedal, but
these do not indicate a malfunc-
tion.
 This ABS has a test mode which
allows the owner to experience
the pulsation at the brake lever or
brake pedal when the ABS is op-
erating. However, special tools are
required, so please consult your
Yamaha dealer.NOTICE
ECA20100
Be careful not to damag e the wheel
sensor or wheel sensor rotor; other-
wise, improper performance of the
ABS will result.
1. Front wheel sensor rotor
2. Front wheel sensor
1. Rear wheel sensor
2. Rear wheel sensor rotorZAUM158912ZAUM1590
12
UB5GE2E0.book Page 15 Thursday, July 30, 2020 3:08 PM

For your safety – pre-operation checks
4-2
4
Rear brake • Check operation.
• If soft or spongy, have Yamaha dealer bleed hydraulic system.
• Check brake pads for wear.
• Replace if necessary.
• Check fluid level in reservoir.
• If necessary, add specified brake fluid to specified level.
• Check hydraulic system for leakage. 6-22, 6-23
Clutch • Check operation.
• Lubricate cable if necessary.
• Check lever free play.
• Adjust if necessary.
6-20
Throttle grip • Make sure that operation is smooth.
• Check throttle grip free play.
• If necessary, have Yamaha dealer adjust throttle grip free play and lubricate ca-
ble and grip housing. 6-16, 6-27
Control ca bles • Make sure that operation is smooth.
• Lubricate if necessary. 6-27
Drive chain • Check chain slack.
• Adjust if necessary.
• Check chain condition.
• Lubricate if necessary.
6-25, 6-26
Wheels an d tires • Check for damage.
• Check tire condition and tread depth.
• Check air pressure.
• Correct if necessary.
6-17, 6-19
Brake an d shift pe dals • Make sure that operation is smooth.
• Lubricate pedal pivoting points if necessary. 6-27
Brake an d clutch levers • Make sure that operation is smooth.
• Lubricate lever pivoting points if necessary.
6-28
Si destan d • Make sure that operation is smooth.
• Lubricate pivot if necessary.
6-29
ITEM CHECKS PAGE
UB5GE2E0.book Page 2 Thursday, July 30, 2020 3:08 PM

Operation and important ri din g points
5-3
5
EAU16674
Shiftin gShifting gears lets you control the
amount of engine power available for
starting off, accelerating, climbing hills,
etc.
The gear positions are shown in the il-
lustration.TIPTo shift the transmission into the neu-
tral position ( ), press the shift pedal
down repeatedly until it reaches the
end of its travel, and then slightly raise
it.
NOTICE
ECA10261
Even with the transmission in
the neutral position, do not
coast for lon g period s of time
with the eng ine off, and d o not
tow the motorcycle for lon g d is-
tances. The transmission is
properly lu bricated only when
the en gine is runnin g. Ina de-
quate lu brication may damag e
the transmission.
 Always use the clutch while
chan gin g g ears to avoi d d am-
a g in g the en gine, transmission,
an d d rive train, which are not
d esi gne d to withstan d the
shock of forced shifting.
EAU85370
To start out an d accelerate
1. Pull the clutch lever to disengage the clutch.
2. Shift the transmission into first gear. The neutral indicator light
should go out.
3. Open the throttle gradually, and at the same time, release the clutch
lever slowly. 4. After starting out, close the throt-
tle, and at the same time, quickly
pull the clutch lever in.
5. Shift the transmission into second gear. (Make sure not to shift the
transmission into the neutral posi-
tion.)
6. Open the throttle part way and gradually release the clutch lever.
7. Follow the same procedure when shifting to the next higher gear.
EAU85380
To decelerate
1. Release the throttle and apply both the front and the rear brakes
smoothly to slow the motorcycle.
2. As the vehicle decelerates, shift to a lower gear.
3. When the engine is about to stall or runs roughly, pull the clutch le-
ver in, use the brakes to slow the
motorcycle, and continue to
downshift as necessary.
4. Once the motorcycle has stopped, the transmission can be
shifted into the neutral position.
1. Neutral position
2. Shift pedalZAUM1592
1 2 3 4 5
6
1
2
N
UB5GE2E0.book Page 3 Thursday, July 30, 2020 3:08 PM

Operation and important rid ing points
5-4
5 The neutral indicator light should
come on and then the clutch lever
can be released.
WARNING
EWA17380

Improper brakin g can cause
loss of control or traction. Al-
ways use b oth brakes an d apply
them smoothly.
 Make sure that the motorcycle
and the en gine have sufficiently
slowe d b efore shiftin g to a low-
er gear. En gag in g a lower gear
when the vehicle or en gine
speed is too hi gh coul d make
the rear wheel lose traction or
the en gine to over-rev. This
coul d cause loss of control, an
acci dent an d injury. It coul d also
cause en gine or drive train dam-
a g e.
EAU16811
Tips for re ducin g fuel con-
sumptionFuel consumption depends largely on
your riding style. Consider the follow-
ing tips to reduce fuel consumption:
 Shift up swiftly, and avoid high en-
gine speeds during acceleration.
 Do not rev the engine while shift-
ing down, and avoid high engine
speeds with no load on the en-
gine.
 Turn the engine off instead of let-
ting it idle for an extended length
of time (e.g., in traffic jams, at traf-
fic lights or at railroad crossings).
EAU17214
Parkin gWhen parking, stop the engine, and
then remove the key from the main
switch.
WARNING
EWA10312
Since the en gine an d exhaust
system can become very hot,
park in a place where pe destri-
ans or chil dren are not likely to
touch them an d b e burne d.
 Do not park on a slope or on soft
groun d, otherwise the vehicle
may overturn, increasin g the
risk of a fuel leak an d fire.
 Do not park near grass or other
flammab le materials which
mi ght catch fire.
UB5GE2E0.book Page 4 Thursday, July 30, 2020 3:08 PM