NOTE:
The fuel tank cap cannot be installed
unless the key is in the lock. In addi-
tion, the key cannot be removed if the
cap is not properly installed and loc-
ked.
EWA10120
s s
WARNING
Make sure that the fuel tank cap is
properly closed and locked before
riding.
EAU13220
Fuel
Make sure that there is sufficient fuel
in the tank. When refueling, be sure to
insert the pump nozzle into the fuel
tank filler hole and to fill the tank to
the bottom of the filler tube as shown.
1. Filing pipe
2. Fuel level
EWA10880
s s
WARNING
Do not overfill the fuel tank,
otherwise it may overflow
when the fuel warms up and
expands.
Avoid spilling fuel on the hot
engine.
ECA10070
CAUTION
Immediately wipe off spilled fuel
with a clean, dry, soft cloth, since
fuel may deteriorate painted surfa-
ces or plastic parts.
EAU13320
Recommended fuel:
REGULAR UNLEADED GASOLINE
ONLY
Fuel tank capacity:
10,7 L (2,82 US gal) (2,35 Imp.gal)
Fuel reserve amount:
1,8 L (0,48 US gal) (0,40 Imp.gal)
ECA11400
CAUTION
Use only unleaded gasoline. The
use of leaded gasoline will cause
severe damage to internal engine
parts, such as the valves and piston
rings, as well as to the exhaust sys-
tem.
Your Yamaha engine has been desig-
ned to use regular unleaded gasoline
with a research octane number of 91
or higher. If knocking (or pinging)
occurs, use a gasoline of a different
brand or premium unleaded fuel. Use
of unleaded fuel will extend spark
plug life and reduce maintenance
costs.
EAU13430
Catalytic converter
This model is equipped with a cataly-
tic converter in the exhaust chamber.
EWA10860
s s
WARNING
The exhaust system is hot after
operation. Make sure that the
exhaust system has cooled down
before doing any maintenance
work.
3
INSTRUMENT AND CONTROL FUNCTIONS
3-6
1
2
1D0-F8199-E2.qxd 20/9/04 11:32 Página 20
EWA10570
s s
WARNING
Have a Yamaha dealer replace
excessively worn tires. Besides
being illegal, operating the
motorcycle with excessively
worn tires decreases riding
stability and can lead to loss of
control.
The replacement of all wheel-
and brake-related parts, inclu-
ding the tires, should be left to
a Yamaha dealer, who has the
necessary professional know-
ledge and experience.
It is not recommended to patch
a punctured tube. If unavoida-
ble, however, patch the tube
very carefully and replace it as
soon as possible with a high-
quality product.
EAU21940
Spoke wheels
To maximize the performance, durabi-
lity, and safe operation of your
motorcycle, note the following points
regarding the specified wheels.
The wheel rims should be chec-
ked for cracks, bends or warpa-
ge, and the spokes for looseness
or damage before each ride. If
any damage is found, have a
Yamaha dealer replace the whe-
el. Do not attempt even the sma-
llest repair to the wheel. A defor-
med or cracked wheel must be
replaced.
The wheel should be balanced
whenever either the tire or wheel
has been changed or replaced.
An unbalanced wheel can result
in poor performance, adverse
handling characteristics, and a
shortened tire life.
Ride at moderate speeds after
changing a tire since the tire sur-
face must first be “broken in” for
it to develop its optimal characte-
ristics.
EAU22041
Adjusting the clutch lever
free play
1. Lock nut
2. Adjusting bolt
3. Free play
The clutch lever free play should mea-
sure 10-15 mm (0,34-0,59 in) as
shown. Periodically check the clutch
lever free play and, if necessary,
adjust it as follows.
1. Loosen the locknut at the clutch
lever.
2. To increase the clutch lever free
play, turn the adjusting bolt in
direction (a). To decrease the
clutch lever free play, turn the
adjusting bolt in direction (b).6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-15
1
2 3
1D0-F8199-E2.qxd 20/9/04 11:32 Página 46
DimensionsOverall length
DT125RE 2210 mm
DT125X 2139 mm
Overall width
795 mm
Overall height
DT125RE 1200 mm
DT125X 1121 mm
Seat height
DT125RE 900 mm
DT125X 886 mm
Wheelbase
DT125RE 1415 mm
DT125X 1396 mm
Ground clearance
DT125RE 300 mm
DT125X 271 mm
Minimum turning radius
DT125RE 2100 mm
DT125X 2016 mm
WeightWith oil and fuel
DT125RE 126.0 kg
DT125X 134.0 kg
EngineEngine type
Liquid cooled 2-stroke
Cylinder arrangement
Forward-inclined single cylinder
Displacement
124.0 cm
3
Bore x stroke
56.0 x 50.7 mmCompression ratio
6.70 :1
Starting system
Electric starter
Lubrication system
Separate lubrication (Yamaha autolube)
Type
YAMALUBE 2-cycle oil or 2-stroke engine
oil (JASO FC g
Engine oil quantityQuantity
1.3 L
Transmission oilType
SAE10W30 type SE motor oil
Oil change quantity
0.75 L
Cooling systemCoolant reservoir capacity (up to the maxi-
mum leve
0.30 L
Radiator capacity (including all routes)
0.92 L
Air filterAir filter element
Wet element
FuelRecommended fuel
Regular unleaded gasoline only
Fuel tank capacity
10.7 L
Fuel reserve amount
1.8 L
CarburetorManufacturer
MIKUNI
Type x quantity
TM28-92 x1
Spark plug(s)Manufacturer/model
NGK/BR8ES
Spark plug gap
0.7-0.8 mm
Clutch type
Wet, multiple-disc
TransmissionPrimary reduction system
Helical gear
Primary reduction ratio
71/22 (3.227)
Secondary reduction system
Chain drive
Secondary reduction ratio
57/16 (3.563)
Transmission type
Constant mesh 6-speed
Operation
Left foot operation
Gear ratio1st
34/12 (2.833)
2nd
30/16 (1.875)
3rd
24/17 (1.412)
4th
24/21 (1.143)
8
SPECIFICATIONS
8-1
1D0-F8199-E2.qxd 20/9/04 11:32 Página 67
5th
22/23 (0.957)
6th
18/22 (0.818)
ChassisFrame type
Semi double cradle
Caster angle
DT125RE 27.00 degree
DT125X 24.50 degree
Trail
DT125RE 107.0 mm
DT125X 73.1 mm
Front tireType
With tube
Size
DT125RE 80/90-21 48P
DT125X 120/70-17 58H
Manufacturer/model
DT125RE MICHELIN/T63
DT125X PIRELLI/Sport Demon
Rear tireType
With tube
Size
DT125RE 110/80-18 58P
DT125X 140/70-17 66H
Manufacturer/model
DT125RE MICHELIN/T63
DT125X PIRELLI/Sport Demon
Maximum load
DT125RE 178 kg
DT125X 180 kg
Tire air pressure (measured on cold
tires)
Loading condition
0-90 kg
Front
DT125RE 150 kPa
DT125X 180 kPa
Rear
DT125RE 175 kPa
DT125X 200 kPa
Loading condition
90-178 kg
Front
DT125RE 175 kPa
DT125X 180 kPa
Rear
200 kPa
Off-road ridingFront
DT125RE 150 kPa
Rear
DT125RE 175 kPa
Front wheelWheel type
Spoke wheel
Rim size
DT125RE 21x1.60
DT125X 17x3.00
Rear wheelWheel type
Spoke wheel
Rim size
DT125RE 18x1.85
DT125X 17x3.50
Front brakeType
Single disc brake
Operation
Right hand operation
Recommended fluid
DOT 4
Rear brakeType
Single disc brake
Operation
Right foot operation
Recommended fluid
DOT 4
Front suspensionType
Telescopic fork
Spring/shock absorber type
Coil spring/oil damper
Wheel travel
DT125RE 270.0 mm
DT125X 200.0 mm
Rear suspensionType
Swingarm (link suspension)
Spring/shock absorber type
Coil spring/gas-oil damper
Wheel travel
DT125RE 260.0 mm
DT125X 230.0 mm
Electrical systemIgnition system
CDI
8
SPECIFICATIONS
8-2
1D0-F8199-E2.qxd 20/9/04 11:32 Página 68
EAU26351
Identification numbers
Record the key identification number,
vehicle identification number and
model label information in the spaces
provided below for assistance when
ordering spare parts from a Yamaha
dealer or for reference in case the
vehicle is stolen.
KEY IDENTIFICATION NUMBER:
VEHICLE IDENTIFICATION NUMBER:
MODEL LABEL INFORMATION:
EAU26381
Key identification number
1. Key identification number
The key identification number is
stamped into the key tag.Record this
number in the space provided and
use it for reference when ordering a
new key.
EAU26400
Vehicle identification number
1. Frame number
The vehicle identification number is
stamped into the steering head
pipe.Record this number in the space
provided.
NOTE:
The vehicle identification number is
used to identify your motorcycle and
may be used to register your
motorcycle with the licensing autho-
rity in your area.
9
CONSUMER INFORMATION
9-1
1
1
1D0-F8199-E2.qxd 20/9/04 11:32 Página 70
EAU26440
Engine serial number
1. Engine serial number
The engine serial number is stamped
into the crankcase.
EAU26480
Model label
1. Model label
The model label is affixed to the frame
under the seat. (See page 3-8.)
Record the information on this label in
the space provided. This information
will be needed when ordering spare
parts from a Yamaha dealer.
9
CONSUMER INFORMATION
9-2
11
1D0-F8199-E2.qxd 20/9/04 11:32 Página 71