engine YAMAHA DT125R 2005 Owner's Manual

Tightening torque:
Spark plug:
20 Nm (2 m•kgf)
NOTE:
If 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. Howe-
ver, the spark plug should be tighte-
ned to the specified torque as soon
as possible.
EAU19950
Transmission oil
1. Oil level window
2. Maximum level mark
3. Minimum level mark
The transmission oil level should be
checked before each ride. In addition,
the transmission oil must be changed
at the intervals specified in the perio-
dic maintenance and lubrication
chart.
To check the transmission oil level
1. Place the vehicle on a level surfa-
ce and hold it in an upright posi-
tion.
NOTE:
Make sure that the vehicle is positio-
ned straight up when checking the oil
level. A slight tilt to the side can result
in a false reading.
1. Plug to fill with oil
2. Start the engine, warm it up for
several minutes, and then turn it
off.
3. Wait a few minutes until the oil
settles, and then check the oil
level through the check window
located at the right side of the
crankcase.
NOTE:
The transmission oil should be at or
above the minimum level mark.
4. If the oil is below the minimum
level mark, remove the oil filler
cap, add sufficient oil of the
recommended type to raise it to
the correct level, and then install
and tighten the cap.
To change the transmission oil
1. Drain bolt
6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-7
2
3
11
1
1D0-F8199-E2.qxd 20/9/04 11:32 Página 38

1. Start the engine, warm it up for
several minutes, and then turn it
off.
2. Place an oil pan under the trans-
mission to collect the used oil.
3. Remove the oil filler cap and
drain bolt to drain the oil from the
transmission.
4. Install the transmission oil drain
bolt, and then tighten it to the
specified torque.
Tightening torque:
Transmission oil drain bolt:
15 Nm (1,5 m•kgf)
5. Add the specified amount of the
recommended transmission oil,
and then install and tighten the oil
filler cap.
Recommended transmission oil:
See page 8-1.
Oil change quantity:
0,8 L (0,85 US qt)
ECA10450
CAUTION
In order to prevent clutch slip-
page (since the transmission
oil also lubricates the clutch),
do not mix any chemical additi-
ves with the oil.
Make sure that no foreign
material enters the transmis-
sion.
6. Start the engine, and then let it
idle for several minutes while
checking the transmission for oil
leakage. If oil is leaking, imme-
diately turn off the engine and
check for the cause.
EAU20070
Coolant
The coolant level should be checked
before each ride. In addition, the coo-
lant must be changed at the intervals
specified in the periodic maintenance
and lubrication chart.
EAU20170
To check the coolant level
1. Place the vehicle on a level surfa-
ce and hold it in an upright posi-
tion.
NOTE:
The coolant level must be chec-
ked on a cold engine since the
level varies with engine tempera-
ture.
Make sure that the vehicle is
positioned straight up when
checking the coolant level. A
slight tilt to the side can result in
a false reading.
2. Remove panel D. (See page 6-6.)
3. Check the coolant level in the
coolant reservoir.
FULL
LOW
6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-8
1D0-F8199-E2.qxd 20/9/04 11:32 Página 39

NOTE:
The coolant should be between the
minimum and maximum level marks.
4. If the coolant is at or below the
minimum level mark, open the
reservoir cap, add coolant to the
maximum level mark, and then
close the reservoir cap.
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.
EWA10380
s s
WARNING
Never attempt to remove the radia-
tor cap when the engine is hot.
5. Install the panel.
NOTE:
If the engine overheats, see page
6-31 for further instructions.
EAU20370
To change the coolant
1. Radiator cap bolt
2. Radiador cap
1. Put the vehicle on a level place.
2. Remove cowling C and panel D.
(See page 6-5 ~ 6-6.)
3. Remove the radiator cap stopper
bolt and the radiator cap.
1. Drain bolt
4. Place a container under the engi-
ne and remove the coolant drain
bolt.
5. Disconnect the coolant reservoir
hose on the reservoir side and
drain the coolant from the reser-
voir.
6. After draining the coolant, tho-
roughly flush the cooling system
with clean tap water.
7. Replace the coolant drain bolt
washer if it is damaged, and then
tighten the coolant drain bolt to
the specified torque.6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-9
2
11
1D0-F8199-E2.qxd 20/9/04 11:32 Página 40

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)
6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-10
1
1D0-F8199-E2.qxd 20/9/04 11:32 Página 41

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.
6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-11
12
1D0-F8199-E2.qxd 20/9/04 11:32 Página 42

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.
6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-12
1
2
1D0-F8199-E2.qxd 20/9/04 11:32 Página 43

EAU22960
To adjust the drive chain slack
1. Axle nut
2. Chain tensioner
1. Loosen the axle nut.
2. To tighten the drive chain, turn
the adjusting plate on each side
of the swingarm in direction (a).
To loosen the drive chain, turn
the adjusting plate on each side
of the swingarm in direction (b),
and then push the rear wheel for-
ward.
NOTE:
Make sure that both adjusting plates
are in the same position for proper
wheel alignment.
ECA10570
CAUTION
Improper drive chain slack will
overload the engine as well as
other vital parts of the motorcycle
and can lead to chain slippage or
breakage. To prevent this from
occurring, keep the drive chain
slack within the specified limits.
3. Tighten the axle nut to the speci-
fied torque.
Tightening torque:
Axle nut:
90 Nm (9,0 m•kgf)
EAU23021
Lubricating the drive chain
The drive chain must be cleaned and
lubricated at the intervals specified in
the periodic maintenance and lubrica-
tion chart, otherwise it will quickly
wear out, especially when riding in
dusty or wet areas. Service the drive
chain as follows.
ECA10581
CAUTION
The drive chain must be lubricated
after washing the motorcycle and
riding in the rain.
1. Clean the drive chain with kero-
sene and a small soft brush.
ECA11120
CAUTION
To prevent damaging the O-rings,
do not clean the drive chain with
steam cleaners, high-pressure
washers or inappropriate solvents.
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive
chain with a special O-ring chain
lubricant.
ECA11110
CAUTION
Do not use engine oil or any other
lubricants for the drive chain, as
they may contain substances that
could damage the O-rings.
6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-20
1 2
1D0-F8199-E2.qxd 20/9/04 11:32 Página 51

EAU23100
Checking and lubricating the
cables
The operation of all control cables
and the condition of the cables
should be checked before each ride,
and the cables and cable ends should
be lubricated if necessary. If a cable is
damaged or does not move smoothly,
have a Yamaha dealer check or repla-
ce it.
Recommended lubricant:
Engine oil
EWA10720
s s
WARNING
Damage to the outer sheath may
interfere with proper cable opera-
tion and will cause the inner cable
to rust. Replace a damaged cable
as soon as possible to prevent
unsafe conditions.
EAU23110
Checking and lubricating the
throttle grip and cable
The operation of the throttle grip
should be checked before each ride.
In addition, the cable should be lubri-
cated or replaced at the intervals spe-
cified in the periodic maintenance
chart.
EAU23120
Adjusting the Autolube pump
The Autolube pump is a vital and sop-
histicated component of the engine,
which must be adjusted by a Yamaha
dealer at the intervals specified in the
periodic maintenance and lubrication
chart.
EAU23131
Checking and lubricating the
brake and shift pedals
The operation of the brake and shift
pedals should be checked before
each ride, and the pedal pivots
should be lubricated if necessary.
Recommended lubricant:
Lithium-soap-based grease (all-pur-
pose grease)
EAU23140
Checking and lubricating the
brake and clutch levers
The operation of the brake and clutch
levers should be checked before each
ride, and the lever pivots should be
lubricated if necessary.
Recommended lubricant:
Lithium-soap-based grease (all-pur-
pose grease)
EAU23200
Checking and lubricating the
sidestand
The operation of the sidestand should
be checked before each ride, and the
sidestand pivot and metal-to-metal
contact surfaces should be lubricated
if necessary.
EWA10730
s s
WARNING
If the sidestand does not move up
and down smoothly, have a Yama-
ha dealer check or repair it.
6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-21
1D0-F8199-E2.qxd 20/9/04 11:32 Página 52

Recommended lubricant:
Lithium-soap-based grease (all-pur-
pose grease)
EAU23271
Checking the front fork
The condition and operation of the
front fork must be checked as follows
at the intervals specified in the perio-
dic maintenance and lubrication
chart.
To check the condition
EWA10750
s s
WARNING
Securely support the motorcycle so
that there is no danger of it falling
over.
Check the inner tubes for scratches,
damage and excessive oil leakage.To check the operation
1. Place the motorcycle on a level
surface and hold it in an upright
position.
2. While applying the front brake,
push down hard on the handle-
bars several times to check if the
front fork compresses and
rebounds smoothly.ECA10590
CAUTION
If any damage is found or the front
fork does not operate smoothly,
have a Yamaha dealer check or
repair it.
EAU23280
Checking the steering
Worn or loose steering bearings may
cause danger. Therefore, the opera-
tion of the steering must be checked
as follows at the intervals specified in
the periodic maintenance and lubrica-
tion chart.
1. Place a stand under the engine to
raise the front wheel off the
ground.
EWA10750
s s
WARNING
Securely support the motorcycle so
that there is no danger of it falling
over.
6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-22
1D0-F8199-E2.qxd 20/9/04 11:32 Página 53

ECA10680
CAUTION
Do not overtighten the screws,
otherwise the lens may break.
EAU24201
Replacing a turn signal light
bulb
1. Screw
2. Lens
3. Bulb
1. Remove the turn signal light lens
by removing the screw.
2. Remove the defective bulb by
pushing it in and turning it coun-
terclockwise.
3. Insert a new bulb into the socket,
push it in, and then turn it clock-
wise until it stops.4. Install the lens by installing the
screw.
ECA11190
CAUTION
Do not overtighten the screw,
otherwise the lens may break.
EAU24350
Supporting the motorcycle
Since this model is not equipped with
a centerstand, follow these precau-
tions when removing the front and
rear wheel or performing other main-
tenance requiring the motorcycle to
stand upright. Check that the
motorcycle is in a stable and level
position before starting any mainte-
nance. A strong wooden box can be
placed under the engine for added
stability.
To service the front wheel
1. Stabilize the rear of the motorcy-
cle by using a motorcycle stand
or, if an additional motorcycle
stand is not available, by placing
a jack under the frame in front of
the rear wheel.2. Raise the front wheel off the
ground by using a motorcycle
stand.
To service the rear wheel
Raise the rear wheel off the ground by
using a motorcycle stand or, if a
motorcycle stand is not available, by
placing a jack either under each side
of the frame in front of the rear wheel
or under each side of the swingarm.
EAU24360
Front wheel
EAU24640
To remove the front wheel
1. Speedometer cable
2. Axle retainer nut (x4)
3. Wheel axle
6
PERIODIC MAINTENANCE AND MINOR REPAIR
6-26
1
3
2
31
2
1D0-F8199-E2.qxd 20/9/04 11:32 Página 57