oil 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

Description
2-2
2
EAU10421
Right view
1
2
3
4
5
6
7
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 6-10)
5. Dipstick (page 6-10)
6. Brake pedal (page 3-14)
7. Rear brake fluid reservoir (page 6-22)UB6GE1E0.book Page 2 Thursday, July 30, 2020 1:08 PM

For your safety – pre-operation checks
4-1
4
EAU1559B
Inspect your vehicle each time you use it to make sure the vehicle is in safe operating 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 acci dent or equipment damag e.
Do not operate the vehicle if you fin d any pro blem. If a pro blem cannot be corrected b y the proce dures provi ded in
this manual, have the vehicle inspecte d b y 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 breather hose and overflow hose for obstructions, cracks or
damage, and check hose connections. 3-16, 3-18
En gine oil • Check oil level in engine.
• If necessary, add recommended oil to specified level.
• Check vehicle for oil leakage. 6-10
Coolant • Check coolant level in reservoir.
• If necessary, add recommended coolant to specified level.
• Check cooling system for leakage. 6-13
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. 6-22, 6-22
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Operation and important ri din g points
5-1
5
EAU15952
Read the Owner’s Manual carefully to
become familiar with all controls. If
there is a control or function you do not
understand, ask your Yamaha dealer.
WARNING
EWA10272
Failure to familiarize yourself with
the controls can lead to loss of con-
trol, which coul d cause an acci dent
or injury.
EAU16831
En gine break-inThere is never a more important period
in the life of your engine than the period
between 0 and 1000 km (600 mi). For
this reason, you should read the fol-
lowing material carefully.
Since the engine is brand new, do not
put an excessive load on it for the first
1000 km (600 mi). The various parts in
the engine wear and polish themselves
to the correct operating clearances.
During this period, prolonged full-throt-
tle operation or any condition that
might result in engine overheating
must be avoided.
EAU16983
0–500 km (0–300 mi)
Avoid prolonged operation above 5000
r/min.
After every hour of operation, stop the
engine, and then let it cool for five to
ten minutes.
Vary the engine speed from time to
time. Do not operate the engine at one
set throttle position. 500–1000 km (300–600 mi)
Avoid prolonged operation above 7500
r/min.
Rev the engine freely through the
gears, but do not use full throttle at any
time.
NOTICE: After 1000 km (600 mi)
of operation, the en gine oil must b e
chan ged , the oil filter cartri dge or el-
ement replace d, an d the oil strainer
cleaned .
[ECA10322]
1000 km (600 mi) and b eyon d
The vehicle can now be operated nor-
mally.NOTICE
ECA10311
 Keep the en gine spee d out of
the tachometer red zone.
 If any en gine trou ble shoul d oc-
cur during the en gine break-in
perio d, imme diately have a
Yamaha dealer check the vehi-
cle.
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Periodic maintenance an d a djustment
6-6
6
20 Si destan d • Check operation.
• Lubricate with lithium-soap-
based grease. √√√√√
21 *Sidestan d switch • Check operation and replace if
necessary. √√√√√√
22 *Front fork • Check operation and for oil leak-
age.
• Replace if necessary. √√√√
23 *Shock a
bsor ber as-
sem bly • Check operation and for oil leak-
age.
• Replace if necessary. √√√√
24 *Rear suspension re-
lay arm an
d con-
nectin g arm
pivotin g points • Check operation.
√√√√
• Lubricate with lithium-soap- based grease. √√
25 En gine oil • Change (warm engine before
draining).
• Check oil level and vehicle for oil leakage. At the initial interval and
every 3000 km (1800 mi) thereafter. √
26 En
gine oil filter ele-
ment • Replace.
√√√√√
27 *Coolin g system • Check coolant level and vehicle
for coolant leakage. √√√√√
• Change. Every 3 years
28 *Front an
d rear
b rake switches • Check operation.
√√√√√√
29 *Movin
g parts an d
cab les • Lubricate.
√√
√√√
NO. ITEM CHECK OR MAINTENANCE JOB
ODOMETER READING
ANNUAL
CHECK
1000 km
(600 mi) 6000 km
(3500 mi) 12000 km
(7000 mi) 18000 km
(10500 mi) 24000 km
(14000 mi)
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Periodic maintenance an d a djustment
6-10
6
EAUM2584
En gine oil an d oil filter ele-
mentThe engine oil level should be checked
before each ride. In addition, the oil
must be changed and the oil filter ele-
ment replaced at the intervals specified
in the periodic maintenance and lubri-
cation chart.
To check the en gine oil level
1. Place the vehicle on a level sur- face and hold it in an upright posi-
tion. A slight tilt to the side can
result in a false reading.
2. Start the engine, warm it up for several minutes, and then turn it
off.
3. Wait a few minutes until the oil set- tles, remove the oil filler cap, wipe
the dipstick clean, insert it back
into the oil filler hole (without
screwing it in), and then remove it
again to check the oil level.
NOTICE: Do not operate the ve-
hicle until you know that the en-
g ine oil level is sufficient.
[ECA10012]
TIPThe engine oil should be between the
minimum and maximum level marks.
4. If the engine oil is below the mini-
mum level mark, add sufficient oil
of the recommended type to raise
it to the correct level.
5. Install the oil filler cap.
To chan ge the en gine oil (with or
without oil filter element replace-
ment) 1. Start the engine, warm it up for several minutes, and then turn it
off.
2. Place an oil pan under the engine to collect the used oil.
3. Remove the engine oil filler cap and the drain bolt along with the
O-ring, compression spring, and
engine oil strainer, to drain the oil
from the crankcase. NOTICE:
When removin g the en gine oil
d rain bolt, the O-rin g, compres-
sion sprin g, an d oil strainer will
fall out. Take care not to lose
these parts.
[ECA11002]
1. Engine oil filler cap
1. Dipstick
2. Maximum level mark
3. Minimum level mark
1
2
3
ZAUE1300
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Periodic maintenance an d a djustment
6-11
6
4. Clean the engine oil strainer with solvent.
TIPSkip steps 5–7 if the oil filter element is
not being replaced.5. Remove the oil filter element coverby removing the bolts. 6. Remove and replace the oil filter
element and O-ring. 7. Install the oil filter element cover
by installing the bolts, then tight-
ening them to the specified
torque.
TIPMake sure that the O-ring is properly
seated.8. Install the engine oil strainer, com-pression spring, O-ring and the
engine oil drain bolt, and then
tighten it to the specified torque.
NOTICE: Before installin g the
en gine oil drain bolt, do not for-
g et to install the O-ring , com-
pression sprin g, an d oil strainer
in position.
[ECA10422]
1. Engine oil drain bolt
2. O-ring
3. Compression spring
4. Strainer
5. Oil pan
1. Bolt
2. Oil filter element cover
1. Oil filter element
2. O-ring
Ti ghtenin g torque:
Oil filter element cover bolt: 10 N·m (1.0 kgf·m, 7.4 lb·ft)
Ti ghtenin g torque:
Engine oil drain bolt: 32 N·m (3.2 kgf·m, 24 lb·ft)
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Periodic maintenance an d a djustment
6-12
6 9. Refill with the specified amount of
the recommended engine oil, and
then install and tighten the oil filler
cap.
NOTICE
ECA11621
In or der to prevent clutch slip-
pa ge (since the en gine oil also
lu bricates the clutch), do not
mix any chemical additives. Do
not use oils with a d iesel speci-
fication of “CD” or oils of a hi gh-
er quality than specifie d. In
a ddition, do not use oils la beled
“ENERGY CONSERVING II” or
hi gher.
 Make sure that no forei gn mate-
rial enters the crankcase.
10. Start the engine, and then let it idle for several minutes while checking
it for oil leakage. If oil is leaking,
immediately turn the engine off
and check for the cause.
11. Turn the engine off, and then check the oil level and correct it if
necessary.
EAU85450
Why Yamalu beYAMALUBE 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.
Recommen ded en gine oil:
See page 8-1.
Oil quantity: Oil change:
0.85 L (0.90 US qt, 0.75 Imp.qt)
With oil filter removal: 0.95 L (1.00 US qt, 0.84 Imp.qt)
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Periodic maintenance an d a djustment
6-23
6
Rear
brake
WARNING
EWA16011
Improper maintenance can result in
loss of b raking a bility. O bserve
these precautions:  Insufficient brake flui d may al-
low air to enter the brake sys-
tem, re ducin g brakin g
performance.
 Clean the filler cap before re-
movin g. Use only DOT 4 brake
flui d from a seale d container. 
Use only the specified b rake flu-
i d ; otherwise, the ru bber seals
may deteriorate, causin g leak-
a g e.
 Refill with the same type of
brake flui d. A dding a brake fluid
other than DOT 4 may result in a
harmful chemical reaction.
 Be careful that water or d ust
d oes not enter the brake flui d
reservoir when refillin g. Water
will si gnificantly lower the boil-
in g point of the flui d an d may re-
sult in vapor lock, an d d ir
t may
clo g the ABS hy draulic unit
valves.
NOTICE
ECA17641
Brake flui d may d amage painte d
surfaces or plastic parts. Always
clean up spilled fluid imme diately.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.
1. Minimum level markSpecifie
d b rake flui d:
DOT 4
1
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Periodic maintenance an d a djustment
6-25
6
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.
TIPUsing 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.
4. Make sure that the drive chain pullers are in the same position,
the drive chain slack is correct,
and the drive chain moves
smoothly.
EAU23026
Cleanin g an d lu bricatin g the
d rive chainThe drive chain must be cleaned and
lubricated at the intervals specified in
the periodic maintenance and lubrica-
tion chart, otherwise it will quickly wear
out, especially when riding in dusty or
wet areas. Service the drive chain as
follows.NOTICE
ECA10584
The drive chain must b e lubricate d
after washin g the motorcycle, ri din g
in the rain or ri din g in wet areas.1. Clean the drive chain with kero-
sene and a small soft brush.
NOTICE: To prevent d amaging
the O-rin gs, do not clean the
d rive chain with steam cleaners,
hi gh-pressure washers or inap-
propriate solvents.
[ECA11122]
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive chain with a special O-ring chain
lubricant. NOTICE: Do not use
en gine oil or any other lu bri-
cants for the drive chain, as they
1. Drive chain slack adjusting bolt
2. Axle nut
3. Alignment marks
4. LocknutZAUM1605
321
4
(b)
(a)
Ti
ghtenin g torques:
Axle nut: 85 N·m (8.5 kgf·m, 63 lb·ft)
Locknut:
15 N·m (1.5 kgf·m, 11 lb·ft)
UB6GE1E0.book Page 25 Thursday, July 30, 2020 1:08 PM