2021 YAMAHA MT-125 Owners Manual

Periodic maintenance an d a djustment
6-29
6
EAU23273
Checkin g the front forkThe condition and operation of the
front fork must be checked as follows
at the intervals specified in the periodic
maintenance and lubrication chart.
To check the con dition
Check the inner tubes for scratches,
damage and excessive oil leakage.
To check the operation 1. Place the vehicle on a level sur- face and hold it in an upright posi-
tion. WARNING! To avoi d injury,
securely support the vehicle so
there is no dan ger of it fallin g
over.
[EWA10752]
2. While applying the front brake, push down hard on the handle-
bars several times to check if the
front fork compresses and re-
bounds smoothly.
NOTICE
ECA10591
If any damag e is foun d or the front
fork does not operate smoothly,
have a Yamaha d ealer check or re-
pair it.
EAU23285
Checkin g the steerin gWorn or loose steering bearings may
cause danger. Therefore, the operation
of the steering must be checked as fol-
lows at the intervals specified in the
periodic maintenance and lubrication
chart.
1. Raise the front wheel off the ground. (See page 6-34.)
WARNING! To avoi d injury, se-
curely support the vehicle so
there is no dan ger of it fallin g
over.
[EWA10752]
2. Hold the lower ends of the front fork legs and try to move them for-
ward and backward. If any free
play can be felt, have a Yamaha
dealer check or repair the steer-
ing.ZAUM1744
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Periodic maintenance an d a djustment
6-30
6
EAU23292
Checkin g the wheel b earingsThe front and rear wheel bearings must
be checked at the intervals specified in
the periodic maintenance and lubrica-
tion chart. If there is play in the wheel
hub or if the wheel does not turn
smoothly, have a Yamaha dealer
check the wheel bearings.
EAU50583
BatteryThe battery is located under the rider
seat. It is a VRLA (valve-regulated lead-
acid) battery. There is no need to check
the electrolyte or to add distilled water.
However, the battery lead connections
need to be checked, and tightened if
necessary.
WARNING
EWA10761
 Electrolyte is poisonous an d
d an gerous since it contains sul-
furic aci d, which causes severe
b urns. Avoi d any contact with
skin, eyes or clothin g an d al- ways shiel
d your eyes when
workin g near b atteries. In case
of contact, ad minister the fol-
lowin g FIRST AID.
EXTERNAL: Flush with plenty of water.
INTERNAL: Drink lar ge quan-
tities of water or milk an d im-
me diately call a physician.
EYES: Flush with water for 15 minutes an d seek prompt
me dical attention.
 Batteries pro duce explosive hy-
d ro gen gas. Therefore, keep
sparks, flames, ci garettes, etc.,
away from the battery an d pro-
vi de sufficient ventilation when
char gin g it in an enclose d
space.
 KEEP THIS AND ALL BATTER-
IES OUT OF THE REACH OF
CHILDREN.
NOTICE
ECA10621
Never attempt to remove the b attery
cell seals, as this would permanently
d amag e the battery.
1. Positive battery lead (red)
2. Battery
3. Negative battery lead (black)
1
2
3
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Periodic maintenance an d a djustment
6-31
6
To char
ge the b attery
Have your Yamaha dealer charge the
battery if it seems to have discharged.
Keep in mind that the battery tends to
discharge more quickly if the vehicle is
equipped with optional electrical ac-
cessories.
NOTICE
ECA16522
To char ge a VRLA (Valve Re gulate d
Lea d Aci d) battery, a special (con-
stant-volta ge) battery char ger is re-
quire d. Usin g a conventional b attery
char ger will damag e the battery.To store the battery
1. If the vehicle will not be used for more than one month, remove the
battery, fully charge it, and then
place it in a cool, dry place.
NOTICE: When removin g the
b attery, be sure to turn the main
switch off, then disconnect the
ne gative lead before discon-
nectin g the positive lea d.
[ECA16304]
2. If the battery will be stored for
more than two months, check it at
least once a month and fully
charge it if necessary. 3. Fully charge the battery before in-
stallation. NOTICE: When install-
in g the b attery, be sure to turn
the main switch off, then con-
nect the positive lea d before
connectin g the ne gative lea d.
[ECA16842]
4. After installation, make sure that
the battery leads are properly con-
nected to the battery terminals.NOTICE
ECA16531
Always keep the b attery charged .
Storin g a dischar ged battery can
cause permanent b attery damag e.
EAUB1116
Replacin g the fusesThe fuse box is located under the seat.
(See page 3-19.)
If a fuse is blown, replace it as follows.
1. Turn the main switch off and turn off the electrical circuit in ques-
tion.
2. Remove the blown fuse, and then install a new fuse of the specified
amperage. WARNING! Do not
use a fuse of a hi gher ampera ge1. Fuse box
2. Spare fuse
3. Headlight fuse
4. ABS control unit fuse
5. Main fuse
6. ABS solenoid fuse
7. ABS motor fuse
8. Fuse tongs
15
7.5
2
1
5
7
.5
1
5
3
0
30
2
1
8
76
543
2
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Periodic maintenance an d a djustment
6-32
6 ratin
g than recommen ded to
avoi d causin g extensive d am-
a g e to the electrical system an d
possi bly a fire.
[EWA15132]
3. Turn the main switch on and turn
on the electrical circuit in question
to check if the device operates.
4. If the fuse immediately blows again, have a Yamaha dealer
check the electrical system.
EAUN2261
Vehicle lig htsThis model is equipped with LED lights
for headlights, auxiliary lights and
brake/tail light. If a light does not come
on, check the fuse and then have a
Yamaha dealer check the vehicle.NOTICE
ECA16581
Do not affix any type of tinte d film or
stickers to the hea dlig ht lens.
EAU24182
Tail/ brake li ghtThis model is equipped with an LED-
type tail/brake light.
If the tail/brake light does not come on,
have a Yamaha dealer check it.
Specifie d fuses:
Main fuse: 15.0 A
ABS motor fuse:
30.0 A
ABS solenoid fuse: 15.0 A
ABS control unit fuse: 2.0 A
Headlight fuse:
7.5 A
1. Auxiliary light
2. Headlight
2 1
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Periodic maintenance an d a djustment
6-33
6
EAU62590
Replacin g a turn sig nal light
b ul b1. 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 overti ghten the screw, oth-
erwise the lens may break.
[ECA11192] EAUM3510
Replacin
g the license plate
lig ht bul b1. 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
1. Turn signal light bulbZAUM1609
1
1. License plate light bulb socket
2. License plate light unit
3. ScrewZAUM1621
2
3
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Periodic maintenance an d a djustment
6-34
6
EAU67131
Supportin g the motorcycleSince this model is not equipped with a
centerstand, use maintenance stands
when removing the front or rear wheel
or when performing other maintenance
that requires the motorcycle to stand
up right.
Check that the motorcycle is in a stable
and level position before starting any
maintenance.
EAU25872
Trou bleshootin gAlthough Yamaha motorcycles receive
a thorough inspection before shipment
from the factory, trouble may occur
during operation. Any problem in the
fuel, compression, or ignition systems,
for example, can cause poor starting
and loss of power.
The following troubleshooting charts
represent quick and easy procedures
for checking these vital systems your-
self. However, should your motorcycle
require any repair, take it to a Yamaha
dealer, whose skilled technicians have
the necessary tools, experience, and
know-how to service the motorcycle
properly.
Use only genuine Yamaha replace-
ment parts. Imitation parts may look
like Yamaha parts, but they are often
inferior, have a shorter service life and
can lead to expensive repair bills.
WARNING
EWA15142
When checkin g the fuel system, do
not smoke, an d make sure there are
no open flames or sparks in the ar-
ea, inclu din g pilot lig hts from water heaters or furnaces. Gasoline or
g
asoline vapors can i gnite or ex-
plod e, causin g severe injury or prop-
erty damag e.
1. Maintenance stand (example)
1
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Periodic maintenance an d a djustment
6-35
6
EAU86350
Trou bleshootin g chart
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the battery.
Supply fuel.
The engine does not start.
Check the battery.
Try starting the engine.4. Compression
There is compression.
There is no compression.
The engine does not start.
Have a Yamaha dealer check the vehicle.Have a Yamaha dealer check the vehicle.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug(s). Have a Yamaha dealer check the vehicle.
The engine does not start.
Check the compression.
Operate the electric starter.2. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.
DryWet
Try starting the engine.
Check the battery lead connections,
and charge the battery if necessary.
The engine does not start.
Check the ignition.
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Periodic maintenance an d a djustment
6-36
6
EAU86420
En gine overheatin g
WARNING
EWAT1041
Do not remove the ra diator cap when the en gine an d ra diator are hot. Scal din g hot flui d an d steam may be
b lown out un der pressure, which coul d cause serious injury. Be sure to wait until the en gine has coole d.
 Place a thick ra g, like a towel, over the ra diator cap, an d then slowly rotate the cap counterclockwise to the
d etent to allow any resi dual pressure to escape. When the hissin g soun d has stoppe d, press d own on the cap
while turnin g it counterclockwise, an d then remove the cap.TIPIf coolant is not available, tap water can be temporarily used instead, provided that it is changed to the recommended cool-
ant as soon as possible.
Wait until the
engine has cooled.
Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer checkand repair the cooling system.Add coolant. (See TIP.)
Start the engine. If the engine overheats again,
have a
Yamaha dealer check
and repair the cooling system.
There is
leakage.
There is
no leakage.
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