YAMAHA MT-125 2015 Workshop Manual

PERIODIC MAINTENANCE AND ADJUSTMENT
6-9
6
EAU19605
Checking the spark plugThe spark plug is an important engine
component, which is easy to check.
Since heat and deposits will cause any
spark plug to slowly erode, the spark
plug should be removed and checked
in accordance with the periodic main-
tenance and lubrication chart. In addi-
tion, the condition of the spark plug
can reveal the condition of the engine.
To remove the spark plug
1. Remove the spark plug cap.
2. Remove the spark plug as shown,
with the spark plug wrench includ-
ed in the owner’s tool kit.To check the spark plug
1. Check that the porcelain insulator
around the center electrode of the
spark plug is a medium-to-light
tan (the ideal color when the vehi-
cle is ridden normally).
TIPIf the spark plug shows a distinctly dif-
ferent color, the engine could be oper-
ating improperly. Do not attempt to
diagnose such problems yourself. In-
stead, have a Yamaha dealer check
the vehicle.
2. Check the spark plug for electrode
erosion and excessive carbon or
other deposits, and replace it if
necessary.
3. Measure the spark plug gap with a
wire thickness gauge and, if nec-
essary, adjust the gap to specifi-
cation.
1. Spark plug cap
1. Spark plug wrench
Specified spark plug:
NGK/CR9E
1. Spark plug gap
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
1
ZAUM0037
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-10
6To install the spark plug
1. Clean the surface of the spark
plug gasket and its mating sur-
face, and then wipe off any grime
from the spark plug threads.
2. Install the spark plug with the
spark plug wrench, and then tight-
en it to the specified torque.
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.3. Install the spark plug cap.
EAUM3490
Engine oil and 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 engine 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-
gine oil level is sufficient.
[ECA10012]
TIPThe engine oil should be between the
minimum and maximum level marks.
Tightening torque:
Spark plug:
12.5 Nm (1.25 m·kgf, 9.04 ft·lbf)
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 AND ADJUSTMENT
6-11
6 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 change the engine oil (with or
without oil filter element replace-
ment)
1. Remove cowling B. (See page
6-8.)
2. Start the engine, warm it up for
several minutes, and then turn it
off.
3. Install the engine oil drain attach-
ment, provided with the owner’s
tool kit, under the drain bolt of the
crankcase.4. Place an oil pan under the engine
to collect the used oil.
5. 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 removing the engine oil
drain bolt, the O-ring, compres-
sion spring, and oil strainer will
fall out. Take care not to lose
these parts.
[ECA11002]
6. Clean the engine oil strainer with
solvent.TIPSkip steps 7–9 if the oil filter element is
not being replaced.7. Remove the oil filter element cover
by removing the bolts.
1. Engine oil drain bolt (crankcase)
2. Engine oil drain attachmentZAUM1229
2
1. Engine oil drain bolt
2. O-ring
3. Compression spring
4. Strainer
5. Oil pan
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-12
68. Remove and replace the oil filter
element and O-ring.9. 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.10. 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 installing the
engine oil drain bolt, do not for-
get to install the O-ring, com-
pression spring, and oil strainer
in position.
[ECA10422]
11. Refill with the specified amount of
the recommended engine oil, and
then install and tighten the oil filler
cap.NOTICE
ECA11621
In order to prevent clutch slip-
page (since the engine oil also
lubricates the clutch), do not
mix any chemical additives. Do
not use oils with a diesel speci-
fication of “CD” or oils of a high-
er quality than specified. In
addition, do not use oils labeled
“ENERGY CONSERVING II” or
higher.
Make sure that no foreign mate-
rial enters the crankcase.
1. Bolt
2. Oil filter element cover
1. Oil filter element
2. O-ring
Tightening torques:
Oil filter element cover bolt:
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Tightening torques:
Engine oil drain bolt:
32 Nm (3.2 m·kgf, 23 ft·lbf)
Recommended engine oil:
See page 8-1.
Oil quantity:
Without oil filter element replace-
ment:
0.95 L (1.00 US qt, 0.84 Imp.qt)
With oil filter element replacement:
1.00 L (1.06 US qt, 0.88 Imp.qt)
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-13
6 12. 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.
13. Turn the engine off, and then
check the oil level and correct it if
necessary.
14. Reset the oil change indicator.
(See page 3-10.)
EAU20071
CoolantThe 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.
EAUM1726
To check the coolant level
1. Place the vehicle on a level sur-
face and hold it in an upright posi-
tion.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.2. Check the coolant level in the
coolant reservoir.TIPThe coolant should be between the
minimum and maximum level marks.
3. If the coolant is at or below the
minimum level mark, remove
cowling A (See page 6-8.), and
then open the reservoir cap.
WARNING! Remove only the
coolant reservoir cap. Never at-
tempt to remove the radiator
cap when the engine is hot.
[EWA15162]
4. Add coolant to the maximum level
mark, and then close the reservoir
cap. NOTICE: If coolant is not
available, use distilled water or
soft tap water instead. Do not
use hard water or salt water
since it is harmful to the engine.1. Coolant reservoir cap
2. Maximum level mark
3. Minimum level markZAUM1207
FULL
LOW
2
3
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-14
6If water has been used instead
of coolant, replace it with cool-
ant as soon as possible, other-
wise the cooling system will not
be protected against frost and
corrosion. If water has been
added to the coolant, have a
Yamaha dealer check the anti-
freeze content of the coolant as
soon as possible, otherwise the
effectiveness of the coolant will
be reduced.
[ECA10473]
5. Install the cowling.
EAU33032
Changing 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 radiator cap when the engine is
hot.
[EWA10382]EAUM2391
Replacing the air filter ele-
ment and cleaning 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.2. If dirt or water is visible, remove
the hose, clean it, and then install
it.
Coolant reservoir capacity (up to
the maximum level mark):
0.25 L (0.26 US qt, 0.22 Imp.qt)
1. Air filter check hose
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-15
6
EAU44735
Checking the engine idling
speedCheck the engine idling speed and, if
necessary, have it corrected by a
Yamaha dealer.
EAU48433
Adjusting the throttle grip free
playThe throttle grip free play should mea-
sure 3.0–5.0 mm (0.12–0.20 in) at the
inner edge of the throttle grip. Periodi-
cally check the throttle grip free play
and, if necessary, adjust it as follows.TIPThe engine idling speed must be cor-
rectly adjusted before checking and
adjusting the throttle grip free play.1. Slide the rubber cover back.
2. Loosen the locknut.3. To increase the throttle grip free
play, turn the adjusting nut in di-
rection (a). To decrease the throt-
tle grip free play, turn the adjusting
nut in direction (b).
4. Tighten the locknut and then slide
the rubber cover to its original po-
sition.
Engine idling speed:
1350–1550 r/min
1. Throttle grip free play
1
1. Rubber cover
2. Adjusting nut
3. LocknutZAUM12081
23
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-16
6
EAU21402
Valve clearanceThe valve clearance changes with use,
resulting in improper air-fuel mixture
and/or engine noise. To prevent this
from occurring, the valve clearance
must be adjusted by a Yamaha dealer
at the intervals specified in the periodic
maintenance and lubrication chart.
EAUM2405
TiresTires are the only contact between the
vehicle and the road. Safety in all con-
ditions of riding depends on a relatively
small area of road contact. Therefore, it
is essential to maintain the tires in good
condition at all times and replace them
at the appropriate time with the speci-
fied tires.
Tire air pressure
The tire air pressure should be
checked and, if necessary, adjusted
before each ride.
WARNING
EWA10504
Operation of this vehicle with im-
proper tire pressure may cause se-
vere injury or death from loss of
control.
The tire air pressure must be
checked and adjusted on cold
tires (i.e., when the temperature
of the tires equals the ambient
temperature).
The tire air pressure must be
adjusted in accordance with the
riding speed and with the totalweight of rider, passenger, car-
go, and accessories approved
for this model.
WARNING
EWA10512
Never overload your vehicle. Opera-
tion of an overloaded vehicle could
cause an accident.Tire air pressure (measured on cold
tires):
0–90 kg (0–198 lb):
Front:
180 kPa (1.80 kgf/cm², 26 psi)
Rear:
200 kPa (2.00 kgf/cm², 29 psi)
MT125 90–180 kg (198–397 lb)
MT125A 90–178 kg (198–392 lb):
Front:
180 kPa (1.80 kgf/cm², 26 psi)
Rear:
225 kPa (2.25 kgf/cm², 33 psi)
Maximum load*:
MT125 180 kg (397 lb)
MT125A 178 kg (392 lb)
* Total weight of rider, passenger, car-
go and accessories
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-17
6 Tire inspection
The tires must be checked before each
ride. If the center tread depth reaches
the specified limit, if the tire has a nail
or glass fragments in it, or if the side-
wall is cracked, have a Yamaha dealer
replace the tire immediately.
TIPThe tire tread depth limits may differ
from country to country. Always com-
ply with the local regulations.
WARNING
EWA10472
Have a Yamaha dealer replace
excessively worn tires. Besides
being illegal, operating the vehi-
cle with excessively worn tires
decreases riding stability and
can lead to loss of control.
The replacement of all wheel
and brake-related parts, includ-
ing the tires, should be left to a
Yamaha dealer, who has the
necessary professional knowl-
edge and experience to do so.
Ride at moderate speeds after
changing a tire since the tire
surface must first be “broken
in” for it to develop its optimal
characteristics.
Tire information
This motorcycle is equipped with tube-
less tires, tire air valves and cast
wheels.
Tires age, even if they have not been
used or have only been used occasion-
ally. Cracking of the tread and sidewall
rubber, sometimes accompanied by
carcass deformation, is an evidence of
ageing. Old and aged tires shall be
checked by tire specialists to ascertain
their suitability for further use.
1. Tire sidewall
2. Tire tread depthMinimum tire tread depth (front and
rear):
1.6 mm (0.06 in)
1. Tire air valve
2. Tire air valve core
3. Tire air valve cap with seal
123
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-18
6
WARNING
EWA10902
The front and rear tires should
be of the same make and de-
sign, otherwise the handling
characteristics of the motorcy-
cle may be different, which
could lead to an accident.
Always make sure that the valve
caps are securely installed to
prevent air pressure leakage.
Use only the tire valves and
valve cores listed below to
avoid tire deflation during a ride.After extensive tests, only the tires list-
ed below have been approved for this
model by Yamaha Motor Co., Ltd.
WARNING
EWA10601
This motorcycle is fitted with super-
high-speed tires. Note the following
points in order to make the most ef-
ficient use of these tires.Use only the specified replace-
ment tires. Other tires may run
the danger of bursting at super
high speeds.
Brand-new tires can have a rel-
atively poor grip on certain road
surfaces until they have been
“broken in”. Therefore, it is ad-
visable before doing any high-
speed riding to ride conserva-
tively for approximately 100 km
(60 mi) after installing a new tire.
The tires must be warmed up
before a high-speed run.
Always adjust the tire air pres-
sure according to the operating
conditions.Front tire:
Size:
100/80-17 M/C 52H(PIRELLI)-
52S(MICHELIN)
Manufacturer/model:
PIRELLI/SPORT DEMON
MICHELIN/PILOT STREET
Tire air valve:
TR412
Valve core:
V3002 (original)
Rear tire:
Size:
130/70-17 M/C 62H(PIRELLI)-
62S(MICHELIN)
Manufacturer/model:
PIRELLI/SPORT DEMON
MICHELIN/PILOT STREET
Tire air valve:
TR412
Valve core:
V3002 (original)
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