2020 YAMAHA MT-125 coolant

Table of contents
Safety information............................1-1
Description........................................2-1
Left view ..........................................2-1
Right view........................................2-2
Controls and instruments ................2-3
Instrument and 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 .....................................3-13
Brake lever ....................................3-14
Brake pedal ...................................3-14
ABS ...............................................3-15
Fuel tank cap.................................3-16
Fuel................................................3-16
Fuel tank overflow hose ................3-18
Catalytic converter ........................3-18
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 and important riding
points.................................................5-1
Engine break-in ...............................5-1
Starting the engine ..........................5-2
Shifting ............................................5-4
Tips for reducing fuel
consumption ................................5-5
Parking ............................................5-6
Periodic maintenance and
adjustment........................................6-1
Tool kit.............................................6-2
Periodic maintenance chart for the
emission control system ..............6-3
General maintenance and
lubrication chart ...........................6-4Removing and installing
cowlings ...................................... 6-7
Checking the spark plug ................. 6-7
Engine oil and oil filter element ....... 6-8
Why Yamalube .............................. 6-11
Coolant ......................................... 6-11
Replacing the air filter element
and cleaning the check hose..... 6-13
Adjusting the engine idling
speed......................................... 6-13
Adjusting the throttle grip free
play ............................................ 6-14
Valve clearance ............................. 6-15
Tires .............................................. 6-15
Cast wheels .................................. 6-18
Adjusting the clutch lever free
play ............................................ 6-18
Checking the front brake lever
free play ..................................... 6-19
Adjusting the brake pedal free
play ............................................ 6-20
Brake light switches ...................... 6-20
Checking the front and rear brake
pads........................................... 6-21
Checking the brake fluid level....... 6-22
Changing the brake fluid............... 6-23
Drive chain slack ........................... 6-23
Cleaning and lubricating the drive
chain .......................................... 6-25
Checking and lubricating the
cables ........................................ 6-25
Checking and lubricating the
throttle grip and cable ............... 6-26
Checking and lubricating the
brake and shift pedals ............... 6-26
Checking and lubricating the
brake and clutch levers ............. 6-27
Checking and lubricating the
sidestand ................................... 6-27
Lubricating the swingarm pivots... 6-28
Checking the front fork ................. 6-28
Checking the steering ................... 6-29
Checking the wheel bearings ....... 6-29
Battery .......................................... 6-30
Replacing the fuses ...................... 6-31
Vehicle lights ................................. 6-32
UB6GE0E0.book Page 1 Wednesday, August 28, 2019 11:11 AM

Description
2-1
2
EAU63371
Left view
1234
65798
1. Fuel tank cap (page 3-16)
2. Battery (page 6-30)
3. Fuses (page 6-31)
4. Tool kit (page 6-2)
5. Sidestand (page 3-20)
6. Air filter check hose
7. Shift pedal (page 3-13)
8. Idle adjusting screw (page 6-13)
9. Coolant reservoir (page 6-11)
UB6GE0E0.book Page 1 Wednesday, August 28, 2019 11:11 AM

Instrument and control functions
3-2
3To unlock the steering
From the “LOCK” position, push the
key and turn it to “OFF”.
EAU4939H
Indicator lights and warning
lights
EAU11022Turn signal indicator light “ ”
This indicator light flashes when a turn
signal light is flashing.
EAU11061Neutral indicator light “ ”
This indicator light comes on when the
transmission is in the neutral position.
EAU11081High beam indicator light “ ”
This indicator light comes on when the
high beam of the headlight is switched
on.
EAU11449Coolant temperature warning
light “ ”
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 6-37.)
1. Push.
2. Turn.
12
1. Shift light
2. Turn signal indicator light Ž
3. High beam indicator light Ž
4. Anti-lock Brake System (ABS) warning
light Ž
5. Engine trouble warning light Ž
6. Coolant temperature warning light Ž
7. Neutral indicator light Ž
ZAUM1566
56 72
3
4
1
ABS
UB6GE0E0.book Page 2 Wednesday, August 28, 2019 11:11 AM

Instrument and control functions
3-3
3 For vehicles with a radiator fan, the ra-
diator fan(s) automatically switch on or
off according to the coolant tempera-
ture.
TIP
When 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-
gine if it is overheating.
EAU73172Engine trouble warning light “ ”
This warning light comes on 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.
TIP
When 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.
EAU69895ABS warning light “ ”
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 warning light does not
turn off after reaching 10 km/h (6
mi/h), or if the warning light comes
on while riding:
Use extra caution to avoid pos-
sible wheel lock during emer-
gency braking.
Have a Yamaha dealer check
the vehicle as soon as possible.
EAU80372Shift light
This light can be set to come on and go
off at select engine speeds. (See page
3-9.)
TIP
When 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.
ABS
UB6GE0E0.book Page 3 Wednesday, August 28, 2019 11:11 AM

For your safety – pre-operation checks
4-1
4
EAU63441
Inspect your vehicle each time you use it to make sure the vehicle is in safe oper-
ating condition. Always follow the inspection and maintenance procedures and
schedules described in the Owner’s Manual.
WARNING
EWA11152
Failure to inspect or maintain the vehicle properly increases the possibility
of an accident or equipment damage. Do not operate the vehicle if you find
any problem. If a problem cannot be corrected by the procedures provided
in this manual, have the vehicle inspected by a Yamaha dealer.
Before using this vehicle, check the following points:
ITEM CHECKS PAGE
Fuel• Check fuel level in fuel tank.
• Refuel if necessary.
• Check fuel line for leakage.
• Check fuel tank overflow hose for obstructions, cracks
or damage, and check hose connection.3-16,
3-18
Engine oil• Check oil level in engine.
• If necessary, add recommended oil to specified level.
• Check vehicle for oil leakage.6-8
Coolant• Check coolant level in reservoir.
• If necessary, add recommended coolant to specified
level.
• Check cooling system for leakage.6-11
Front 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.6-21,
6-22
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.6-21,
6-22
Clutch• Check operation.
• Lubricate cable if necessary.
• Check lever free play.
• Adjust if necessary.6-18
UB6GE0E0.book Page 1 Wednesday, August 28, 2019 11:11 AM

Periodic maintenance and adjustment
6-6
6
EAU72750
TIP
The air filter needs more frequent service if you are riding in unusually wet or
dusty areas.
Hydraulic brake service
• Regularly check and, if necessary, correct the brake fluid level.
• Every two years replace the internal components of the brake master cyl-
inders and calipers, and change the brake fluid.
• Replace the brake hoses every four years and if cracked or damaged.
26Engine oil filter el-
ement• Replace.√√√√√
27*Cooling system• Check coolant level and vehicle
for coolant leakage.√√√√√
• Change. Every 3 years
28*Front and rear
brake switches• Check operation.√√√√√√
29*Moving parts and
cables• Lubricate.√√√√√
30*Throttle grip hous-
ing and cable• Check operation and free play.
• Adjust the throttle cable free
play if necessary.
• Lubricate the throttle grip hous-
ing and cable.√√√√√
31*Lights, signals and
switches• Check operation.
• Adjust headlight beam.√√√√√√ NO. ITEM
X 1000 km CHECK OR
MAINTENANCE JOB
X 1000 miODOMETER
READING
ANNUAL CHECK
16121824
0.6 3.5 7 10.5 14
UB6GE0E0.book Page 6 Wednesday, August 28, 2019 11:11 AM

Periodic maintenance and adjustment
6-11
6
EAU85450
Why Yamalube
YAMALUBE oil is a Genuine YAMAHA
Part born of the engineers’ passion
and belief that engine oil is an impor-
tant liquid engine component. We form
teams of specialists in the fields of me-
chanical engineering, chemistry, elec-
tronics and track testing, and have
them develop the engine together with
the oil it will use. Yamalube oils take full
advantage of the base oil’s qualities
and blend in the ideal balance of addi-
tives to make sure the final oil clears
our performance standards. Thus,
Yamalube mineral, semisynthetic and
synthetic oils have their own distinct
characters and value. Yamaha’s expe-
rience gained over many years of re-
search and development into oil since
the 1960’s helps make Yamalube the
best choice for your Yamaha engine.
EAU20071
Coolant
The coolant level should be checked
before each ride. In addition, the cool-
ant must be changed at the intervals
specified in the periodic maintenance
and lubrication chart.
EAUE4091To check the coolant level
1. Place the vehicle on a level sur-
face.
2. Remove cowling A. (See page
6-7.)
3. Hold the vehicle in an upright po-
sition.
TIP
The coolant level must be
checked on a cold engine since
the level varies with engine tem-
perature.
Make sure that the vehicle is posi-
tioned straight up when checking
the coolant level. A slight tilt to the
side can result in a false reading.
4. Check the coolant level in the
coolant reservoir.
TIP
The coolant should be between the
minimum and maximum level marks.
UB6GE0E0.book Page 11 Wednesday, August 28, 2019 11:11 AM

Periodic maintenance and adjustment
6-12
65. If the coolant is at or below the
minimum level mark, remove the
coolant reservoir cap protector by
removing the bolt then remove the
coolant reservoir cap.
6. Add coolant to the maximum level
mark, and then install the coolant
reservoir cap. WARNING! Re-move only the coolant reservoir
cap. Never attempt to remove
the radiator cap when the en-
gine is hot.
[EWA15162] NOTICE: If
coolant is not available, use dis-
tilled water or soft tap water in-
stead. Do not use hard water or
salt water since it is harmful to
the engine. If water has been
used instead of coolant, replace
it with coolant as soon as possi-
ble, otherwise the cooling sys-
tem will not be protected
against frost and corrosion. If
water has been added to the
coolant, have a Yamaha dealer
check the antifreeze content of
the coolant as soon as possible,
otherwise the effectiveness of
the coolant will be reduced.
[ECA10473]
7. Install the coolant reservoir cap
protector.
8. Install the cowling.
EAU33032Changing the coolant
The coolant must be changed at the in-
tervals specified in the periodic mainte-
nance and lubrication chart. Have a
Yamaha dealer change the coolant.
WARNING! Never attempt to remove
the radiator cap when the engine is
hot.
[EWA10382]
1. Coolant reservoir
2. Maximum level mark
3. Minimum level mark
1. Coolant reservoir cap protector
1. Coolant reservoir cap
Coolant reservoir capacity (up to
the maximum level mark):
0.15 L (0.16 US qt, 0.13 Imp.qt)
UB6GE0E0.book Page 12 Wednesday, August 28, 2019 11:11 AM