2002 YAMAHA TDR 125 engine

6-8
PERIODIC MAINTENANCE AND MINOR REPAIR
6 To install the spark plug
1. Measure the spark plug gap with
a wire thickness gauge and, if
necessary, adjust the gap to
specification.
2. Clean the surface of the spark
plug gasket and its mating sur-
face, and then wipe off any grime
from the spark plug threads.
3. Install the spark plug with the
spark plug wrench, and then
tighten it to the specified torque.
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.
However, the spark plug should be
tightened to the specified torque as
soon as possible.4. Install the spark plug cap.
EAU04272
Transmission oil
Transmission oil
The transmission oil level should be
checked before each ride. In addition,
the transmission oil must be changed
at the intervals specified in the peri-
odic maintenance and lubrication
chart.
To check the transmission oil level
1. Place the motorcycle on a level
surface and hold it in an upright
position.NOTE:
Make sure that the motorcycle is
positioned straight up when checking
the oil level. 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.
a
a. Spark plug gap
Spark plug gap:
0.7–0.8 mm
Tightening torque:
Spark plug:
20 Nm (2.0 m0kgf)
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6-9
PERIODIC MAINTENANCE AND MINOR REPAIR
63. 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 rec-
ommended type to raise it to the
correct level, and then install and
tighten the cap.To change the transmission oil
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.
5. Add the specified amount of the
recommended transmission oil,
and then install and tighten the
oil filler cap.
1
2
1
1
1. Check window
2. Minimum level mark1. Oil filler cap 1. Transmission oil drain bolt
Tightening torque:
Transmission oil drain bolt:
15 Nm (1.5 m0kgf)
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6-10
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EC000077
cC8In order to prevent clutch slip-
page (since the transmission
oil also lubricates the clutch),
do not mix any chemical addi-
tives with the oil.
8Make 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, immedi-
ately turn off the engine and
check for the cause.
EAU03761
CoolantTo check the coolant level
1. Place the motorcycle on a level
surface and hold it in an upright
position.NOTE:
8The coolant level must be
checked on a cold engine since
the level varies with engine tem-
perature.
8Make sure that the motorcycle is
positioned 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.NOTE:
The coolant should be between the
minimum and maximum level marks.3. 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.
1
2
1. Maximum level mark
2. Minimum level mark
Recommended transmission oil:
See page 8-1.
Oil quantity:
Periodic oil change:
0.75 L
Total amount (dry transmission):
0.8 L
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6-11
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EW000067
wNever attempt to remove the radia-
tor cap when the engine is hot.NOTE:
If the engine overheats, see page
6-43 for further instructions.
EAU03746
To change the coolant
1. Place the motorcycle on a level
surface and let the engine cool if
necessary.
2. Remove the seat. (See page
3-12 for seat removal and instal-
lation procedures.)
3. Remove cowling B. (See page
6-6 for cowling removal and
installation procedures.)
4. Remove the radiator cap.
EW000067
wNever attempt to remove the radia-
tor cap when the engine is hot.
5. Place a container under the
engine to collect the used
coolant.
6. Remove the coolant drain bolt
and disconnect the hose on the
side of the reservoir to drain the
reservoir.
7. After the coolant is completely
drained, thoroughly flush the
cooling system with clean tap
water.
8. Install the coolant drain bolt, and
then tighten it to the specified
torque.
1
1
1. Radiator cap 1. Coolant drain bolt
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6-12
PERIODIC MAINTENANCE AND MINOR REPAIR
6
NOTE:
Check the washer for damage and
replace it if necessary.9. Connect the hose to the coolant
reservoir.10. Pour the recommended coolant
into the radiator until it is full.
EC000080
cC8If 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.
8If water has been used instead
of coolant, replace it with
coolant as soon as possible,
otherwise the engine may not
be sufficiently cooled and the
cooling system will not be pro-
tected against frost and corro-
sion.
8If 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.11. Install the radiator cap, start the
engine, let it idle for several min-
utes, and then turn it off.
1
1. Hose
Tightening torque:
Coolant drain bolt:
8 Nm (0.8 m0kgf)
Antifreeze/water mixture ratio:
1:1
Recommended antifreeze:
High-quality ethylene glycol
antifreeze containing corrosion
inhibitors for aluminum engines
Coolant quantity:
Total amount:
1.05 L
Coolant reservoir capacity:
0.35 L
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6-13
PERIODIC MAINTENANCE AND MINOR REPAIR
612. Remove the radiator cap to
check the coolant level in the
radiator. If necessary, add suffi-
cient coolant until it reaches the
top of the radiator, and then
install the radiator cap.
13. Check the coolant level in the
reservoir. If necessary, remove
the coolant reservoir cap by
removing the screw and retainer,
add coolant to the maximum
level mark, and then install the
coolant reservoir cap and retain-
er by installing the screw.14. Start the engine, and then check
the vehicle for coolant leakage. If
coolant is leaking, have a
Yamaha dealer check the cool-
ing system.
15. Install the cowling and the seat.
EAU03747
Cleaning the air filter
elementThe air filter element should be
cleaned at the intervals specified in
the periodic maintenance and lubrica-
tion chart. Clean the air filter element
more frequently if you are riding in
unusually wet or dusty areas.
1. Remove the seat. (See page
3-12 for seat removal and instal-
lation procedures.)
2. Remove cowlings A and B. (See
page 6-6 for cowling removal
and installation procedures.)
3. Remove the fuel tank bolt.
21
4
5
3
1
1. Coolant reservoir tank cap
2. Retainer
3. Screw
4. Maximum level mark
5. Minimum level mark1. Bolt
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6-14
PERIODIC MAINTENANCE AND MINOR REPAIR
6 4. Lift the front of the fuel tank to
position the fuel tank away from
the air filter case. (Do not discon-
nect the fuel hoses!)
EW000071
w8Make sure that the fuel tank is
well supported.
8Do not tilt or pull the fuel tank
too much, otherwise the fuel
hoses may come loose, which
could cause fuel leakage.
5. Remove the relays by pulling
them off their holders, and the air
filter case cover by removing the
screws.6. Pull the sponge material out,
clean it with solvent, and then
squeeze the remaining solvent
out.
7. Apply oil of the recommended
type to the entire surface of the
sponge material, and then
squeeze the excess oil out.
NOTE:
The sponge material should be wet
but not dripping.
1
3
3
2
1
1. Relay (×2)
2. Air filter case cover
3. Screw (×7)1. Sponge material
Recommended oil:
2-stroke engine oil
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6-15
PERIODIC MAINTENANCE AND MINOR REPAIR
68. Insert the sponge material into
the air filter case.
EC000082
cC8Make sure that the air filter ele-
ment is properly seated in the
air filter case.
8The engine should never be
operated without the air filter
element installed, otherwise
the piston and/or cylinder may
become excessively worn.9. Install the air filter case cover by
installing the screws, and then
install the relays.
10. Place the fuel tank in the original
position, and then install the bolt.
EW000131
wMake sure that the fuel hoses and
vacuum hose are properly con-
nected and routed, and not
pinched. Replace any damaged
hoses.11. Install the seat and the cowlings.
EAU00629
Adjusting the carburetorThe 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
described in the following section,
however, may be serviced by the
owner as part of routine mainte-
nance.
EC000094
cCThe carburetor has been set and
extensively tested at the Yamaha
factory. Changing these settings
without sufficient technical knowl-
edge may result in poor perfor-
mance of or damage to the engine.
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