YAMAHA DT125R 2005 Service Manual

Tightening torque:
Coolant drain bolt:
10 Nm (1,0 m•kgf)
8. Connect the coolant reservoir
hose.
9. Pour the recommended coolant
into the radiator until it is full.
Recommended antifreeze:
High quality ethylene glycol antifree-
ze containing corrosion inhibitors for
aluminum engines
Antifreeze/water mixing ratio:
1:1
Coolant quantity:
Radiator capacity (including all rou-
tes):
0,92 L (0,97 US qt)
Coolant reservoir capacity:
0,3 L (0,32 US qt)
ECA10470
CAUTION
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.
If water has been used instead
of coolant, replace it with coo-
lant as soon as possible, other-
wise the engine may not be
sufficiently cooled and the coo-
ling system will not be protec-
ted against frost and corrosion.
If water has been added to the
coolant, have a Yamaha dealer
check the antifreeze content of
the coolant as soon as possi-
ble, otherwise the effective-
ness of the coolant will be
reduced.
10. Install the radiator cap.
11. Run the engine several minutes.
Stop the engine and recheck the
coolant level in the radiator. If it is
low, add more coolant until it rea-
ches the top of the radiator.
12. Install the radiator cap stopper
bolt.
13. Fill the coolant reservoir with
coolant up to maximum level.
14. Install the coolant reservoir cap
and check for coolant leakage.
NOTE:
If any leakage is found, ask a Yamaha
dealer to inspect the cooling system.
15. Install the cowling and the panel.
EAU20831
Cleaning the air filter
element and check hose
The air filter element should be clea-
ned at the intervals specified in the
periodic maintenance and lubrication
chart. Clean the air filter element more
frequently if you are riding in unu-
sually wet or dusty areas. In addition,
the air filter check hose must be fre-
quently checked and cleaned if
necessary.
1. Screws (x3)
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To clean the air filter element
1. Remove panel E. (See page 6-6.)
2. Remove the air filter case cover
by removing the screws.
3. Pull the air filter element out.
1. Guide
2. Filter
4. Remove the sponge material
from the air filter element frame,
clean it with solvent, and then
squeeze the remaining solvent
out.5. Apply oil of the recommended
type to the entire surface of the
sponge material, and then sque-
eze the excess oil out.
NOTE:
The sponge material should be wet
but not dripping.
Recommended oil:
Foam air filter oil
6. Pull the sponge material over the
air filter element frame.
7. Insert the element into the air fil-
ter case.
ECA10480
CAUTION
Make sure that the air filter ele-
ment is properly seated in the
air filter case.
The engine should never be
operated without the air filter
element installed, otherwise
the piston(s) and/or cylinder(s)
may become excessively worn.
8. Install the air filter case cover by
installing the screws.
9. Install the panel.To clean the air filter check hose
1. Check the hose at the bottom 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.
EAU21280
Adjusting the carburetor
The carburetor is an important part of
the engine and requires very sophisti-
cated adjustment. Therefore, most
carburetor adjustments should be left
to a Yamaha dealer, who has the
necessary professional knowledge
and experience. The adjustment des-
cribed in the following section, howe-
ver, may be serviced by the owner as
part of routine maintenance.
ECA10550
CAUTION
The carburetor has been set and
extensively tested at the Yamaha
factory. Changing these settings
without sufficient technical know-
ledge may result in poor perfor-
mance of or damage to the engine.
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EAU21340
Adjusting the engine idling
speed
1. Idle adjusting bolt
The engine idling speed must be
checked and, if necessary, adjusted
as follows at the intervals specified in
the periodic maintenance and lubrica-
tion chart.
The engine should be warm before
making this adjustment.
NOTE:
The engine is warm when it
quickly responds to the throttle.
A diagnostic tachometer is nee-
ded to make this adjustment.
1. Attach the tachometer to the
spark plug lead.2. Check the engine idling speed
and, if necessary, adjust it to spe-
cification by turning the throttle
stop screw. To increase the engi-
ne idling speed, turn the screw in
direction (a). To decrease the
engine idling speed, turn the
screw in direction (b).
Engine idling speed:
1250-1450 r/min
NOTE:
If the specified idling speed cannot be
obtained as described above, have a
Yamaha dealer make the adjustment.
EAU21370
Adjusting the throttle cable
free play
(a) Free play
The throttle cable free play should
measure 3-5 mm (0,11-0,19 in) at the
throttle grip. Periodically check the
throttle cable free play and, if neces-
sary, adjust it as follows.
NOTE:
The engine idling speed must be
correctly adjusted before checking
and adjusting the throttle cable free
play.
1. Lock nut
2. Adjusting nut
1. Loosen the locknut.
2. To increase the throttle cable free
play, turn the adjusting nut in
direction (a). To decrease the
throttle cable free play, turn the
adjusting nut in direction (b).
3. Tighten the locknut.
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EAU21590
Tires
To maximize the performance, durabi-
lity, and safe operation of your
motorcycle, note the following points
regarding the specified tires.
Tire air pressure
The tire air pressure should be chec-
ked and, if necessary, adjusted befo-
re each ride.
EWA10500
s s
WARNING
The tire air pressure must be
checked and adjusted on cold
tires (i.e., when the temperatu-
re of the tires equals the
ambient temperature).
The tire air pressure must be
adjusted in accordance with
the riding speed and with the
total weight of rider, passenger,
cargo, and accessories appro-
ved for this model.
Tire air pressure (measured on cold
tires):
DT125R
Up to 90 kg (198 lb):
Front:
150 kPa (21,8 psi) (1,5 kgf/cm
2)
Rear:
175 kPa (25,4 psi) (1,75 kgf/cm
2)
90 kg (198 lb) to maximum load:
Front:
175 kPa (25,4 psi) (1,75 kgf/cm
2)
Rear:
200 kPa (28,9 psi) (2 kgf/cm
2)
Maximum load*:
178 kg (392 lb)
DT125X
Up to 90 kg (198 lb):
Front:
180 kPa (26,1 psi) (1,8 kgf/cm
2)
Rear:
200 kPa (28,9 psi) (2 kgf/cm
2)
90 kg (198 lb) to maximum load:
Front:
180 kPa (26,1 psi) (1,8 kgf/cm
2)
Rear:
200 kPa (28,9 psi) (2 kgf/cm
2)
Maximum load*:
180 kg (396 lb)
* Total weight of rider, passenger, car-
go and accessories
EWA11200
s s
WARNING
Because loading has an enormous
impact on the handling, braking,
performance and safety characte-
ristics of your vehicle, you should
keep the following precautions in
mind.
NEVER OVERLOAD THE VEHI-
CLE! Operation of an overloa-
ded motorcycle may result in
tire damage, loss of control, or
severe injury. Make sure that
the total weight of rider, pas-
senger, cargo, and accessories
does not exceed the specified
maximum load for the vehicle.
Do not carry along loosely pac-
ked items, which can shift
during a ride.
Securely pack the heaviest
items close to the center of the
vehicle and distribute the
weight evenly on both sides.
Adjust the tire air pressure with
regard to the load.
Check the tire condition and air
pressure before each ride.
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Tire inspection
1.Wear limit
2. Side wall
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 sidewall is cracked, have a Yama-
ha dealer replace the tire immediately.
Minimum tire tread depth (front and
rear):
1.6 mm (0.06 in)
NOTE:
The tire tread depth limits may differ
from country to country. Always
comply with the local regulations.
Tire information
This motorcycle is equipped with tube
tires.
EWA10460
s s
WARNING
The front and rear tires should
be of the same make and
design, otherwise the handling
characteristics of the vehicle
cannot be guaranteed.
After extensive tests, only the
tires listed below have been
approved for this model by
Yamaha Motor España, S.A.
DT125R
Front tire:
Size:
80/90-21 48P
Manufacturer/model:
MICHELIN / T63
Rear tire:
Size:
110/80-18 58P
Manufacturer/model:
MICHELIN / T63
DT125X
Front tire:
Size:
120/70-17 58H
Manufacturer/model:
Pirelli/Sport Demon
Rear tire:
Size:
140/70-17 66H
Manufacturer/model:
Pirelli/Sport Demon
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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
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NOTE:
If the specified clutch lever free play
could be obtained as described abo-
ve, tighten the locknut and skip the
rest of the procedure, otherwise pro-
ceed as follows.
3. Fully turn the adjusting bolt at the
clutch lever in direction (a) to loo-
sen the clutch cable.
1. Lock nut
2. Adjusting nut
4. Loosen the locknut at the crank-
case.
5. To increase the clutch lever free
play, turn the adjusting nut in
direction (a). To decrease the
clutch lever free play, turn the
adjusting nut in direction (b).6. Tighten the locknut at the clutch
lever and the crankcase.
EAU22092
Adjusting the brake lever
free play
1. Lock nut
2. Adjusting bolt
3. Free play
The brake lever free play should mea-
sure 2-5 mm (0,07 ~ 0,19 in) as
shown. Periodically check the brake
lever free play and, if necessary,
adjust it as follows.
1. Loosen the locknut at the brake
lever.2. To increase the brake lever free
play, turn the adjusting screw in
direction (a). To decrease the bra-
ke lever free play, turn the adjus-
ting screw in direction (b).
3. Tighten the locknut.
EWA10630
s s
WARNING
After adjusting the brake lever
free play, check the free play
and make sure that the brake is
working properly.
A soft or spongy feeling in the
brake lever can indicate the
presence of air in the hydraulic
system. If there is air in the
hydraulic system, have a
Yamaha dealer bleed the sys-
tem before operating the
motorcycle. Air in the hydraulic
system will diminish the bra-
king performance, which may
result in loss of control and an
accident.
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EAU22192
Adjusting the brake pedal
position and free play
1. Footrest
(a) Brake pedal position
EWA10670
s s
WARNING
It is advisable to have a Yamaha
dealer make these adjustments.
Brake pedal position
The top of the brake pedal should be
positioned approximately 12-15 mm
(0,47-0,49 in) below the top of the
footrest. Periodically check the brake
pedal position and, if necessary,
adjust it as follows.
1. Loosen the locknut at the brake
pedal.2. To raise the brake pedal, turn the
adjusting bolt in direction (a). To
lower the brake pedal, turn the
adjusting bolt in direction (b).
3. Tighten the locknut.
EWA11230
s s
WARNING
After adjusting the brake pedal
position, the brake pedal free play
must be adjusted.
Brake pedal free play
The brake pedal free play should
measure 10-15 mm (0,34-0,59 in) as
shown. Periodically check the brake
pedal free play and, if necessary,
adjust it as follows.
To increase the brake pedal free play,
turn the adjusting nut at the brake rod
in direction (a). To decrease the brake
pedal free play, turn the adjusting nut
in direction (b).
EWA10680
s s
WARNING
After adjusting the drive chain
slack or removing and installing
the rear wheel, always check
the brake pedal free play.
If proper adjustment cannot be
obtained as described, have a
Yamaha dealer make this
adjustment.
After adjusting the brake pedal
free play, check the operation
of the brake light.
EAU22270
Adjusting the rear brake light
switch
1. Brake light swicht
2. Adjusting nut
The rear brake light switch, which is
activated by the brake pedal, is pro-
perly adjusted when the brake light
comes on just before braking takes
effect. If necessary, adjust the brake
light switch as follows.
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Turn the adjusting nut while holding
the rear brake light switch in place. To
make the brake light come on earlier,
turn the adjusting nut in direction (a).
To make the brake light come on later,
turn the adjusting nut in direction (b).
EAU22340
Checking the front and rear
brake pads
1. Wear limit indicator
The front and rear brake pads must
be checked for wear at the intervals
specified in the periodic maintenance
and lubrication chart. To check the
brake pad wear, measure the lining
thickness. If the lining thickness is
less than 0,8 mm (0,03 in), have a
Yamaha dealer replace the brake
pads as a set.
EWA10250
s s
WARNING
If a malfunction is noted, have a
Yamaha dealer check the system
before riding.
1. Wear indicator
EAU22580
Checking the brake fluid level
1. Minimum level mark
Insufficient brake fluid may allow air
to enter the brake system, possibly
causing it to become ineffective.Before riding, check that the brake
fluid is above the minimum level mark
and replenish if necessary. A low bra-
ke fluid level may indicate worn brake
pads and/or brake system leakage. If
the brake fluid level is low, be sure to
check the brake pads for wear and
the brake system for leakage.
Observe these precautions:
When checking the fluid level,
make sure that the top of the
brake fluid reservoir is level.
1. Minimum level mark

Use only the recommended qua-
lity brake fluid, otherwise the rub-
ber seals may deteriorate, cau-
sing leakage and poor braking
performance.
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Recommended brake fluid:
DOT 4
Refill with the same type of brake
fluid. Mixing fluids may result in a
harmful chemical reaction and
lead to poor braking performan-
ce.
Be careful that water does not
enter the brake fluid reservoir
when refilling. Water will signifi-
cantly lower the boiling point of
the fluid and may result in vapor
lock.
Brake fluid may deteriorate pain-
ted surfaces or plastic parts.
Always clean up spilled fluid
immediately.
As the brake pads wear, it is nor-
mal for the brake fluid level to
gradually go down. However, if
the brake fluid level goes down
suddenly, have a Yamaha dealer
check the cause.
EAU22730
Changing the brake fluid
Have a Yamaha dealer change the
brake fluid at the intervals specified in
the NOTE after the periodic mainte-
nance and lubrication chart. In addi-
tion, 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.
EAU22770
To check the drive chain slack
(a) Chain tension
1. Place the motorcycle on a level
surface and hold it in an upright
position.
NOTE:
When checking and adjusting the dri-
ve chain slack, the motorcycle should
be positioned straight up and there
should be no weight on it.
2. Shift the transmission into the
neutral position.
3. Move the rear wheel by pushing
the motorcycle to locate the tigh-
test portion of the drive chain,
and then measure the drive chain
slack as shown.
Drive chain slack:
45-55 mm (1,76-2,15 in)
4. If the drive chain slack is inco-
rrect, adjust it as follows.
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