2021 YAMAHA MT-125 periodic maintenance

Periodic maintenance an d a djustment
6-7
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 cylinders and calipers, and change the brake fluid.
• Replace the brake hoses every four years and if cracked or damaged.30 *Throttle g
rip hous-
in g an d ca ble • Check operation and free play.
• Adjust the throttle cable free play
if necessary.
• Lubricate the throttle grip housing and cable. √√√√√
31 *Li
ghts, si gnals an d
switches • Check operation.
• Adjust headlight beam.
√√√√√√
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
6-8
6
EAU18782
Removin g an d installin g cowl-
in gsThe cowlings shown need to be re-
moved to perform some of the mainte-
nance jobs described in this chapter.
Refer to this section each time a cowl-
ing needs to be removed and installed.
EAU46742
Cowlin g A
To remove the cowlingRemove the bolts, and then take the
cowling off. To install the cowling
Place the cowling in the original posi-
tion, and then install the bolts.
EAU19623
Checkin
g the spark plu gThe spark plug is an important engine
component, which should be checked
periodically, preferably by a Yamaha
dealer. Since heat and deposits will
cause any spark plug to slowly erode,
it should be removed and checked in
accordance with the periodic mainte-
nance and lubrication chart. In addi-
tion, the condition of the spark plug
can reveal the condition of the engine.
The porcelain insulator around the
center electrode of the spark plug
should be a medium-to-light tan (the
ideal color when the vehicle is ridden
normally). If the spark plug shows a
distinctly different color, the engine
could be operating improperly. Do not
attempt to diagnose such problems
yourself. Instead, have a Yamaha deal-
er check the vehicle.
If the spark plug shows signs of elec-
trode erosion and excessive carbon or
other deposits, it should be replaced.
1. Cowling AZAUM1738
1
1. Bolt
1
Specified spark plu g:
NGK/MR8E9
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Periodic maintenance an d a djustment
6-9
6
Before installing a spark plug, the
spark plug gap should be measured
with a wire thickness gauge and, if
necessary, adjusted to specification.
Clean the surface of the spark plug
gasket and its mating surface, and
then wipe off any grime from the spark
plug threads.
TIPIf a torque wrench is not available
when installing a spark plug, a good
estimate of the correct torque is 1/4–
1/2 turn past finger tight. However, the
spark plug should be tightened to the
specified torque as soon as possible.
EAU36112
CanisterThis model is equipped with a canister
to prevent the discharging of fuel vapor
into the atmosphere. Before operating
this vehicle, make sure to check the
following:
 Check each hose connection.
 Check each hose and canister for
cracks or damage. Replace if
damaged.
 Make sure that the canister
breather is not blocked, and if
necessary, clean it.
1. Spark plug gapSpark plu g g ap:
0.8–0.9 mm (0.031–0.035 in)
Ti ghtenin g torque:
Spark plug: 12.5 N·m (1.25 kgf·m, 9.22 lb·ft)
1
ZAUM0037
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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
6-13
6
EAUS1203
CoolantThe coolant level should be checked
regularly. In addition, the coolant must
be changed at the intervals specified in
the periodic maintenance chart.TIPIf genuine Yamaha coolant is not avail-
able, use an ethylene glycol antifreeze
containing corrosion inhibitors for alu-
minum engines and mix with distilled
water at a 1:1 ratio.
EAUE4091
To check the coolant level
1. Place the vehicle on a level sur- face.
2. Remove cowling A. (See page 6-8.)
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.TIPThe coolant should be between the
minimum and maximum level marks.
5. If the coolant is at or below theminimum level mark, remove the
coolant reservoir cap protector by
removing the bolt then remove the
coolant reservoir cap.
Recommen ded coolant:
YAMALUBE coolant
Coolant quantity: Coolant reservoir (max level mark):0.15 L (0.16 US qt, 0.13 Imp.qt)
Radiator (including all routes): 0.49 L (0.52 US qt, 0.43 Imp.qt)
1. Coolant reservoir
2. Maximum level mark
3. Minimum level mark
1. Coolant reservoir cap protector
1. Coolant reservoir cap
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Periodic maintenance an d a djustment
6-14
6 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 ra diator cap when the en-
g ine is hot.
[EWA15162]
NOTICE: If
coolant is not availa ble, use dis-
tille d water or soft tap water in-
stea d. Do not use har d water or
salt water since it is harmful to
the en gine. If water has been
use d instea d of coolant, replace
it with coolant as soon as possi-
b le, otherwise the coolin g sys-
tem will not be protected
a g ainst frost an d corrosion. If
water has b een added to the
coolant, have a Yamaha d ealer
check the antifreeze content of
the coolant as soon as possi ble,
otherwise the effectiveness of
the coolant will b e reduced.
[ECA10473]
7. Install the coolant reservoir cap
protector.
8. Install the cowling.
EAU33032
Chan gin g the coolant
The coolant must be changed at the in-
tervals specified in the periodic main-
tenance and lubrication chart. Have a
Yamaha dealer change the coolant.
WARNING! Never attempt to remove the ra diator cap when the en gine is
hot.
[EWA10382] EAUM2391
Replacin
g the air filter ele-
ment an d cleanin g the check
hoseThe air filter element should be re-
placed at the intervals specified in the
periodic maintenance and lubrication
chart. Have a Yamaha dealer replace
the air filter element more frequently if
you are riding in unusually wet or dusty
areas. In addition, the air filter check
hose must be frequently checked and
cleaned if necessary.
To clean the air filter check hose
1. Check the hose on the side of the air filter case for accumulated dirt
or water.
Coolant reservoir capacity (up to
the maximum level mark):0.15 L (0.16 US qt, 0.13 Imp.qt)
1. Air filter check hoseZAUM1739
1
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