Page 53 of 96

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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Page 65 of 96

PERIODIC MAINTENANCE AND ADJUSTMENT
6-23
6 Use only the specified brake flu-
id; otherwise, the rubber seals
may deteriorate, causing leak-
age.
Refill with the same type of
brake fluid. Adding a brake fluid
other than DOT 4 may result in a
harmful chemical reaction.
Be careful that water or dust
does not enter the brake fluid
reservoir when refilling. Water
will significantly lower the boil-
ing point of the fluid and may re-
sult in vapor lock, and dirt may
clog the ABS hydraulic unit
valves.
NOTICE
ECA17641
Brake fluid may damage painted
surfaces or plastic parts. Always
clean up spilled fluid immediately.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 brakefluid level goes down suddenly, have a
Yamaha dealer check the cause before
further riding.
EAU22733
Changing the brake fluidHave a Yamaha dealer change the
brake fluid at the intervals specified in
the periodic maintenance and lubrica-
tion chart. In addition, have the oil seals
of the master cylinders and calipers as
well as the brake hoses replaced at the
intervals listed below or whenever they
are damaged or leaking.
Oil seals: Replace every two
years.
Brake hoses: Replace every four
years.
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-33
6
EAUM3501
Replacing the headlight bulbThis model is equipped with a halogen
bulb headlight. If the headlight bulb
burns out, replace it as follows.NOTICE
ECA10651
Take care not to damage the follow-
ing parts:
Headlight bulb
Do not touch the glass part of
the headlight bulb to keep it free
from oil, otherwise the transpar-
ency of the glass, the luminosity
of the bulb, and the bulb life will
be adversely affected. Thor-
oughly clean off any dirt and fin-
gerprints on the headlight bulb
using a cloth moistened with al-
cohol or thinner.
Headlight lens
Do not affix any type of tinted
film or stickers to the headlight
lens.
Do not use a headlight bulb of a
wattage higher than specified.
1. Remove the headlight unit by re-
moving the bolts on each side.
2. Disconnect the headlight coupler,
and then remove the headlight
bulb cover.3. Remove the headlight bulb holder
by turning it counterclockwise,
and then remove the burnt-out
bulb.1. Do not touch the glass part of the bulb.
1. BoltZAUM12201
1. Headlight bulb cover
2. Headlight coupler
1. Headlight bulb
2. Headlight bulb holderZAUM1221
2
1
ZAUM1222
2
1
U5D7E4E0.book Page 33 Thursday, July 10, 2014 3:01 PM
Page 89 of 96

SPECIFICATIONS
8-1
8
Dimensions:Overall length:
1950 mm (76.8 in)
Overall width:
745 mm (29.3 in)
Overall height:
1025 mm (40.4 in)
Seat height:
810 mm (31.9 in)
Wheelbase:
1350 mm (53.1 in)
Ground clearance:
140 mm (5.51 in)
Minimum turning radius:
2500 mm (98.4 in)Weight:Curb weight:
MT125 138 kg (304 lb)
MT125A 140 kg (309 lb)Engine:Engine type:
Liquid cooled 4-stroke, SOHC
Cylinder arrangement:
Single cylinder
Displacement:
124 cm³
Bore × stroke:
52.0 × 58.6 mm (2.05 × 2.31 in)
Compression ratio:
11.2 : 1
Starting system:
Electric starter
Lubrication system:
Wet sump
Engine oil:Recommended brand:
YAMALUBE
Type:
SAE 10W-30, 10W-40, 15W-40, 20W-40 or
20W-50
Recommended engine oil grade:
API service SG type or higher, JASO
standard MA
Engine oil quantity:
Without oil filter element replacement:
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)Coolant quantity:Coolant reservoir (up to the maximum level
mark):
0.25 L (0.26 US qt, 0.22 Imp.qt)
Radiator (including all routes):
1.00 L (1.06 US qt, 0.88 Imp.qt)Air filter:Air filter element:
Dry element
Fuel:Recommended fuel:
Premium unleaded gasoline (Gasohol (E10)
acceptable)
Fuel tank capacity:
11.5 L (3.04 US gal, 2.53 Imp.gal)
Fuel reserve amount:
3.0 L (0.79 US gal, 0.66 Imp.gal)Fuel injection:Throttle body:
ID mark:
5D78 10Spark plug(s):Manufacturer/model:
NGK/CR9E
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)Clutch:Clutch type:
Wet, multiple-discTransmission:Primary reduction ratio:
73/24 (3.042)
Final drive:
Chain
Secondary reduction ratio:
48/14 (3.429)
Transmission type:
Constant mesh 6-speed
Operation:
Left foot operation
Gear ratio:
1st:
34/12 (2.833)
–20 –10 0
1020 30 40 50 C 10 30 50 70 90 110 0 130 F
SAE 10W-30
SAE 15W-40SAE 20W-40SAE 20W-50
SAE 10W-40SAE 10W-50
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Page 90 of 96

SPECIFICATIONS
8-2
8
2nd:
30/16 (1.875)
3rd:
30/22 (1.364)
4th:
24/21 (1.143)
5th:
22/23 (0.957)
6th:
21/25 (0.840)
Chassis:Frame type:
Semi double cradle
Caster angle:
25.00 °
Trail:
89 mm (3.5 in)Front tire:Type:
Tubeless
Size:
100/80-17 M/C 52H(PIRELLI)-
52S(MICHELIN)
Manufacturer/model:
PIRELLI/SPORT DEMON
Manufacturer/model:
MICHELIN/PILOT STREETRear tire:Type:
Tubeless
Size:
130/70-17 M/C 62H(PIRELLI)-
62S(MICHELIN)Manufacturer/model:
PIRELLI/SPORT DEMON
Manufacturer/model:
MICHELIN/PILOT STREET
Loading:Maximum load:
MT125 180 kg (397 lb)
MT125A 178 kg (392 lb)
(Total weight of rider, passenger, cargo
and accessories)Tire air pressure (measured on cold
tires):Loading condition:
0–90 kg (0–198 lb)
Front:
180 kPa (1.80 kgf/cm², 26 psi)
Rear:
200 kPa (2.00 kgf/cm², 29 psi)
Loading condition:
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)Front wheel:Wheel type:
Cast wheel
Rim size:
17xMT2.75Rear wheel:Wheel type:
Cast wheelRim size:
17 x MT3.75
Front brake:Type:
Single disc brake
Operation:
Right hand operation
Specified brake fluid:
DOT 4Rear brake:Type:
Single disc brake
Operation:
Right foot operation
Specified brake fluid:
DOT 4Front suspension:Type:
Telescopic fork
Spring/shock absorber type:
Coil spring/oil damper
Wheel travel:
130 mm (5.1 in)Rear suspension:Type:
Swingarm (link suspension)
Spring/shock absorber type:
Coil spring/oil damper
Wheel travel:
114 mm (4.5 in)Electrical system:Ignition system:
TCI
U5D7E4E0.book Page 2 Thursday, July 10, 2014 3:01 PM