warning light YAMAHA MT-125 2021 Owners Manual

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
Seat .............................................. 3-19
Helmet holder ............................... 3-20
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 ................. 6-8
Canister ........................................... 6-9
Engine oil and oil filter element ..... 6-10
Why Yamalube .............................. 6-12
Coolant.......................................... 6-13
Replacing the air filter element
and cleaning the check hose..... 6-14
Adjusting the engine idling speed ......................................... 6-15
Adjusting the throttle grip free play ............................................ 6-16 Valve clearance............................. 6-16
Tires .............................................. 6-17
Cast wheels .................................. 6-19
Adjusting the clutch lever free
play ............................................ 6-19
Checking the front brake lever free play..................................... 6-20
Adjusting the brake pedal free
play ............................................ 6-21
Brake light switches ..................... 6-21
Checking the front and rear brake pads .......................................... 6-22
Checking the brake fluid level ...... 6-22
Changing the brake fluid .............. 6-24
Drive chain slack........................... 6-24
Cleaning and lubricating the drive chain.......................................... 6-25
Checking and lubricating the cables ........................................ 6-26
Checking and lubricating the
throttle grip and cable ............... 6-26
Checking and lubricating the brake and shift pedals............... 6-27
Checking and lubricating the brake and clutch levers ............. 6-27
Checking and lubricating the
sidestand................................... 6-28
Lubricating the rear suspension ... 6-28
Checking the front fork ................. 6-29
Checking the steering................... 6-29
Checking the wheel bearings ....... 6-30UB6GE1E0.book Page 1 Thursday, July 30, 2020 1:08 PM

Instrument and control functions
3-1
3
EAU10462
Main switch/steerin g lockThe main switch/steering lock controls
the ignition and lighting systems, and is
used to lock the steering. The various
positions are described below.
EAU85050
ON
All electrical circuits are supplied with
power and the vehicle lights are turned
on. The engine can be started. The key
cannot be removed.TIP To prevent battery discharge, do
not leave the key in the on position
without the engine running.
 The headlight comes on automat-
ically when the engine is started. 
The headlight will stay on until the
key is turned to “OFF”, even if the
engine stalls.
EAU10662
OFF
All electrical systems are off. The key
can be removed.
WARNING
EWA10062
Never turn the key to “OFF” or
“LOCK” while the vehicle is movin g.
Otherwise the electrical systems will
b e switche d off, which may result in
loss of control or an acci dent.
EAU10696
LOCK
The steering is locked and all electrical
systems are off. The key can be re-
moved. To lock the steering
1. Turn the handlebars all the way to
the left or right.
2. With the key in the “OFF” position, push the key in and turn it to
“LOCK”.
3. Remove the key.TIPIf the steering will not lock, try turning
the handlebars back to the right or left
slightly.1. Push.
2. Turn.12
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Instrument and control functions
3-2
3
To unlock the steering
From the “LOCK” position, push the
key and turn it to “OFF”.
EAU4939N
In
dicator li ghts an d warnin g
lig hts
EAU11022
Turn si gnal in dicator li ght “ ”
This indicator light flashes when a turn
signal light is flashing.
EAU11061
Neutral in dicator li ght “ ”
This indicator light comes on when the
transmission is in the neutral position.
EAU11081
Hi gh beam in dicator li ght “ ”
This indicator light comes on when the
high beam of the headlight is switched
on.
EAU11449
Coolant temperature warnin g
li g ht “ ”
This warning light comes on when the
engine is overheating. If this occurs,
stop the engine immediately and allow
the engine to cool. (See page 6-36.)
For vehicles with a radiator fan, the ra-
diator fan(s) automatically switch on or
off according to the coolant tempera-
ture.TIPWhen the vehicle is turned on, the light
will come on for a few seconds, and
then go off. If the light does not come
on, or if the light remains on, have a
Yamaha dealer check the vehicle. NOTICE
ECA10022
Do not continue to operate the en-
g ine if it is overheatin g.
1. Push.
2. Turn.12
1. Shift light
2. Turn signal indicator light “ ”
3. High beam indicator light “ ”
4. Anti-lock Brake System (ABS) warning
light “ ”
5. Malfunction indicator light “ ”
6. Coolant temperature warning light “ ”
7. Neutral indicator light “ ”ZAUM15665 6 7
2
3
4
1
ABS
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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
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Instrument and control functions
3-4
3
TIPWhen the vehicle is turned on, the light
will come on for a few seconds and
then go off. If the light does not come
on, have a Yamaha dealer check the
vehicle.
EAUM4011
Multi-function meter unit
WARNING
EWA12423
Be sure to stop the vehicle before
makin g any settin g chan ges to the
multi-function meter unit. Chan gin g
settin gs while ri din g can distract the
operator an d increase the risk of an
acci dent.The multi-function meter unit is
equipped with the following:
 a speedometer
 a clock
 a fuel meter
 a VVA indicator
 a tachometer 
a transmission gear display
 a multi-function display
 a shift timing indicator light
 a self diagnostic device
TIPExcept when accessing the
brightness screen and shift timing
indicator light control mode or
when displaying the welcome
screen, the key must be turned
to “ ” before you can use the
“SELECT” and “RESET” buttons
to adjust the multi-function meter.
 For the UK: To switch between ki-
lometers and miles, press and
hold the “SELECT” button.
1. “SELECT” button
2. “RESET” buttonZAUM1567
1
2
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Instrument and control functions
3-12
3
for all six characters. After the
sixth character is set, all charac-
ters will flash twice and the setting
mode will automatically end.
Self-d iagnostic device
This model is equipped with a self-di-
agnostic device for various electrical
circuits.
If a problem is detected in any of those
circuits, the engine trouble warning
light will come on and the display will
indicate an error code.
If the display indicates any error codes,
note the code number, and then have
a Yamaha dealer check the vehicle.
NOTICE
ECA11591
If the display in dicates an error
co de, the vehicle shoul d b e checked
as soon as possi ble in or der to avoi d
en gine damag e.
EAU1234R
Handle bar switchesLeft
Ri ght
1. Self-diagnostic deviceZAUM1582
1
1. Pass switch “ ”
2. Dimmer switch “ / ”
3. Horn switch “ ”
4. Turn signal switch “ / ”
1. Start/Engine stop switch “ / / ”
12
3
4
1
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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 rotorZAUM173412ZAUM1590
12
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Instrument and control functions
3-16
3
EAU13077
Fuel tank capTo open the fuel tank cap
Open the fuel tank cap lock cover, in-
sert the key, and then turn it 1/4 turn
clockwise. The lock will be released
and the fuel tank cap can be opened.
To close the fuel tank cap
With the key still inserted, push down
the fuel tank cap. Turn the key 1/4 turn
counterclockwise, remove it, and then
close the lock cover.
TIPThe fuel tank cap cannot be closed un-
less the key is in the lock. In addition,
the key cannot be removed if the cap is
not properly closed and locked.
WARNING
EWA11092
Make sure that the fuel tank cap is
properly close d after fillin g fuel.
Leakin g fuel is a fire hazar d.
EAU13222
FuelMake sure there is sufficient gasoline in
the tank.
WARNING
EWA10882
Gasoline an d gasoline vapors are
extremely flammab le. To avoid fires
an d explosions an d to re duce the
risk of injury when refuelin g, follow
these instructions.1. Before refueling, turn off the en- gine and be sure that no one is sit-
ting on the vehicle. Never refuel
while smoking, or while in the vi-
cinity of sparks, open flames, or
other sources of ignition such as
the pilot lights of water heaters
and clothes dryers.
2. Do not overfill the fuel tank. When refueling, be sure to insert the
pump nozzle into the fuel tank filler
hole. Stop filling when the fuel
reaches the bottom of the filler
tube. Because fuel expands when
it heats up, heat from the engine or
the sun can cause fuel to spill out
of the fuel tank.
1. Fuel tank cap lock cover
2. Unlock.
1
2
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Operation and important rid ing points
5-2
5
EAU86690
Startin g the eng ineThe ignition circuit cut-off system will
enable starting when:
 the transmission is in the neutral
position or
 the transmission is in gear, the
sidestand is up, and the clutch le-
ver is pulled.
To start the engine1. Turn the main switch on and set the engine stop switch to the run
position.
2. Confirm the indicator and warning light(s) come on for a few sec-
onds, and the go off. (See page
3-2.)TIPDo not start the engine if the en-
gine trouble warning light remains
on.
 The ABS warning light should
come on and stay on until the ve-
hicle reaches a speed of 10 km/h
(6 mi/h).
NOTICE
ECA24110
If a warnin g or in dicator li ght does
not work as d escribed a bove, have a
Yamaha dealer check the vehicle.3. Shift the transmission into the
neutral position.
4. Start the engine by pushing the start switch.
5. Release the start switch when the engine starts, or after 5 seconds.
Wait 10 seconds before pressing
the switch again to allow battery
voltage to restore.NOTICE
ECA11043
For maximum en gine life, never ac-
celerate har d when the en gine is
col d!
EAU45312
TIPThis model is equipped with a lean an-
gle sensor to stop the engine in case of
a turnover. In this case, turn the main
switch off and then on. Failing to do so
will prevent the engine from starting
even though the engine will crank
when pushing the start switch.
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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.
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