YAMAHA DT125R 2002 Manual Online

6-43
PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU03087
TroubleshootingAlthough Yamaha motorcycles
receive a thorough inspection before
shipment from the factory, trouble
may occur during operation. Any
problem in the fuel, compression, or
ignition systems, for example, can
cause poor starting and loss of
power.
The following troubleshooting charts
represent quick and easy procedures
for checking these vital systems your-
self. However, should your motorcy-
cle require any repair, take it to a
Yamaha dealer, whose skilled techni-
cians have the necessary tools,
experience, and know-how to service
the motorcycle properly.
Use only genuine Yamaha replace-
ment parts. Imitation parts may look
like Yamaha parts, but they are often
inferior, have a shorter service life
and can lead to expensive repair
bills.
EAU01806
To install the rear wheel
1. Install the drive chain onto the
rear sprocket, and then insert the
wheel axle from the left side.NOTE:
Make sure that there is enough
space between the brake pads
before inserting the brake disc
between the pads.2. Install the swingarm end bolts,
and then lower the rear wheel so
that it is on the ground.
3. Adjust the drive chain slack.
(See page 6-27 for drive chain
slack adjustment procedures.)
4. Tighten the axle nut and
swingarm end bolts to the speci-
fied torques.
Tightening torques:
Axle nut:
90 Nm (9.0 m0kgf)
Swingarm end bolts:
3 Nm (0.3 m0kgf)
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6-44
PERIODIC MAINTENANCE AND MINOR REPAIR
6
Check if there is fuel1. Fuel
Enough fuel.
No fuel.
Go to compression check.
Supply fuel.
Engine doesn’t start, go to compression check.
Use kickstarter.2. Compression
There is compression.
No compression.
Go to ignition check.
Ask a Yamaha dealer to
Remove spark plug3. Ignition
Wet.
Dry.
Wipe clean with dry cloth and correct
Ask a Yamaha dealer to inspect.
Engine doesn’t start, ask a YamahaOpen throttle half-way and start
in the fuel tank.
and check electrodes.spark gap or replace spark plug. the engine.
dealer to inspect. inspect.
EAU03108
Troubleshooting charts
EW000125
wKeep away open flames and do not smoke while checking or working on the fuel system.
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6-45
PERIODIC MAINTENANCE AND MINOR REPAIR
6
Wait until the
Check the coolant level in the
Level is OK.Level is low, check the
NoLeakage.
Ask a Yamaha dealer to inspectAdd coolant. (See NOTE.)
Restart the engine. If the engine overheats again, ask a
engine has cooled.reservoir tank and/or radiator.cooling system for leakage.
Yamaha dealer to inspect and repair the cooling system.leakage.
and repair the cooling system.
4. Engine overheating
EW000070
w8Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be
blown out under pressure, which could cause serious injury. Be sure to wait until the engine has cooled.
8After removing the radiator cap retaining bolt, place a thick rag, like a towel, over the radiator cap, and then
slowly rotate the cap counterclockwise to the detent to allow any residual pressure to escape. When the
hissing sound has stopped, press down on the cap while turning it counterclockwise, and then remove the
cap.NOTE:
If it is difficult to get the recommended coolant, tap water can be temporarily used, provided that it is changed to the rec-
ommended coolant as soon as possible.
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7-1
EAU03521
MOTORCYCLE CARE AND STORAGE
7
CareWhile the open design of a motorcy-
cle reveals the attractiveness of the
technology, it also makes it more vul-
nerable. Rust and corrosion can
develop even if high-quality compo-
nents are used. A rusty exhaust pipe
may go unnoticed on a car, however,
it detracts from the overall appear-
ance of a motorcycle. Frequent and
proper care does not only comply
with the terms of the warranty, but it
will also keep your motorcycle looking
good, extend its life and optimize its
performance.Before cleaning
1. Cover the muffler outlet with a
plastic bag after the engine has
cooled down.
2. Make sure that all caps and cov-
ers as well as all electrical cou-
plers and connectors, including
the spark plug cap, are tightly
installed.
3. Remove extremely stubborn dirt,
like oil burnt onto the crankcase,
with a degreasing agent and a
brush, but never apply such
products onto seals, gaskets,
sprockets, the drive chain and
wheel axles. Always rinse the dirt
and degreaser off with water.Cleaning
ECA00010
cC8Avoid using strong acidic
wheel cleaners, especially on
spoked wheels. If such prod-
ucts are used on hard-to-
remove dirt, do not leave the
cleaner on the affected area
any longer than instructed.
Also, thoroughly rinse the area
off with water, immediately dry
it, and then apply a corrosion
protection spray.
8Improper cleaning can damage
windshields, cowlings, panels
and other plastic parts. Use
only a soft, clean cloth or
sponge with mild detergent
and water to clean plastic.
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7-2
MOTORCYCLE CARE AND STORAGE
78Do not use any harsh chemical
products on plastic parts. Be
sure to avoid using cloths or
sponges which have been in
contact with strong or abra-
sive cleaning products, sol-
vent or thinner, fuel (gasoline),
rust removers or inhibitors,
brake fluid, antifreeze or elec-
trolyte.
8Do not use high-pressure
washers or steam-jet cleaners
since they cause water seep-
age and deterioration in the
following areas: seals (of
wheel and swingarm bearings,
fork and brakes), electric com-
ponents (couplers, connec-
tors, instruments, switches
and lights), breather hoses
and vents.8For motorcycles equipped
with a windshield: Do not use
strong cleaners or hard
sponges as they will cause
dulling or scratching. Some
cleaning compounds for plas-
tic may leave scratches on the
windshield. Test the product
on a small hidden part of the
windshield to make sure that it
does not leave any marks. If
the windshield is scratched,
use a quality plastic polishing
compound after washing.
After normal useRemove dirt with warm water, a mild
detergent, and a soft, clean sponge,
and then rinse thoroughly with clean
water. Use a toothbrush or bottle-
brush for hard-to-reach areas.
Stubborn dirt and insects will come
off more easily if the area is covered
with a wet cloth for a few minutes
before cleaning.After riding in the rain, near the sea
or on salt-sprayed roadsSince sea salt or salt sprayed on
roads during winter are extremely
corrosive in combination with water,
carry out the following steps after
each ride in the rain, near the sea or
on salt-sprayed roads.NOTE:
Salt sprayed on roads in the winter
may remain well into spring.1. Clean the motorcycle with cold
water and a mild detergent, after
the engine has cooled down.
ECA00012
cCDo not use warm water since it
increases the corrosive action of
the salt.2. Apply a corrosion protection
spray on all metal, including
chrome- and nickel-plated, sur-
faces to prevent corrosion.
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7-3
MOTORCYCLE CARE AND STORAGE
7 After cleaning
1. Dry the motorcycle with a
chamois or an absorbing cloth.
2. Immediately dry the drive chain
and lubricate it to prevent it from
rusting.
3. Use a chrome polish to shine
chrome, aluminum and stainless-
steel parts, including the exhaust
system. (Even the thermally
induced discoloring of stainless-
steel exhaust systems can be
removed through polishing.)
4. To prevent corrosion, it is recom-
mended to apply a corrosion pro-
tection spray on all metal, includ-
ing chrome- and nickel-plated,
surfaces.
5. Use spray oil as a universal
cleaner to remove any remaining
dirt.
6. Touch up minor paint damage
caused by stones, etc.
7. Wax all painted surfaces.8. Let the motorcycle dry complete-
ly before storing or covering it.
EWA00001
w8Make sure that there is no oil
or wax on the brakes or tires.
If necessary, clean the brake
discs and brake linings with a
regular brake disc cleaner or
acetone, and wash the tires
with warm water and a mild
detergent.
8Before operating the motorcy-
cle test its braking perfor-
mance and cornering behav-
ior.
ECA00013
cC8Apply spray oil and wax spar-
ingly and make sure to wipe
off any excess.
8Never apply oil or wax to any
rubber and plastic parts, but
treat them with a suitable care
product.
8Avoid using abrasive polish-
ing compounds as they will
wear away the paint.NOTE:
Consult a Yamaha dealer for advice
on what products to use.
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7-4
MOTORCYCLE CARE AND STORAGE
7
StorageShort-term
Always store your motorcycle in a
cool, dry place and, if necessary, pro-
tect it against dust with a porous
cover.
ECA00014
cC8Storing the motorcycle in a
poorly ventilated room or cov-
ering it with a tarp, while it is
still wet, will allow water and
humidity to seep in and cause
rust.
8To prevent corrosion, avoid
damp cellars, stables (because
of the presence of ammonia)
and areas where strong chemi-
cals are stored.
Long-term
Before storing your motorcycle for
several months:
1. Follow all the instructions in the
“Care” section of this chapter.
2. For motorcycles equipped with a
fuel cock that has an “OFF” posi-
tion: Turn the fuel cock lever to
“OFF”.
3. Drain the carburetor float cham-
ber by loosening the drain bolt;
this will prevent fuel deposits
from building up. Pour the
drained fuel into the fuel tank.
4. Fill up the fuel tank and add fuel
stabilizer (if available) to prevent
the fuel tank from rusting and the
fuel from deteriorating.
5. Perform the following steps to
protect the cylinder, piston rings,
etc. from corrosion.a. Remove the spark plug cap
and spark plug.
b. Pour a teaspoonful of engine
oil into the spark plug bore.
c. Install the spark plug cap onto
the spark plug, and then place
the spark plug on the cylinder
head so that the electrodes
are grounded. (This will limit
sparking during the next step.)
d. Turn the engine over several
times with the starter. (This
will coat the cylinder wall with
oil.)
e. Remove the spark plug cap
from the spark plug, and then
install the spark plug and the
spark plug cap.
EWA00003
wTo prevent damage or injury from
sparking, make sure to ground the
spark plug electrodes while turn-
ing the engine over.
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7-5
MOTORCYCLE CARE AND STORAGE
7 6. Lubricate all control cables and
the pivoting points of all levers
and pedals as well as of the
sidestand/centerstand.
7. Check and, if necessary, correct
the tire air pressure, and then lift
the motorcycle so that both of its
wheels are off the ground.
Alternatively, turn the wheels a
little every month in order to pre-
vent the tires from becoming
degraded in one spot.
8. Cover the muffler outlet with a
plastic bag to prevent moisture
from entering it.
9. Remove the battery and fully
charge it. Store it in a cool, dry
place and charge it once a
month. Do not store the battery
in an excessively cold or warm
place (less than 0 °C) or more
than 30 °C). For more informa-
tion on storing the battery, see
page 6-34.
NOTE:
Make any necessary repairs before
storing the motorcycle.
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8-1
EAU01038
SPECIFICATIONS
8
Specifications
Model DT125R
Dimensions
Overall length 2,170 mm
2,235 mm (N, S, SF, CH, A only)
Overall width 830 mm
Overall height 1,255 mm
Seat height 885 mm
Wheel base 1,415 mm
Ground clearance 315 mm
Minimum turning radius 2,100 mm
Basic weight (with oil and
full fuel tank)127 kg
129 kg (CH, A only)
Engine
Engine type Liquid-cooled 2-stroke
Cylinder arrangement Forward-inclined single
cylinder
Displacement 124 cm
3
Bore ×Stroke 56.0 ×50.7 mm Compression ratio 6.7:1
Starting system Kickstarter
Lubrication system Separate lubrication
(Yamaha Autolube)
Engine oil (2-cycle)
Type 2-stroke engine oil
Capacity
Total amount 1.2 L
Transmission oil
Type SAE 10W30 type SE motor oil
Capacity
Periodic oil change 0.75 L
Total amount 0.8 L
Cooling system capacity
(total amount)0.92 L
Air filterWet type element
Fuel
Type REGULAR UNLEADED
GASOLINE ONLY
Fuel tank capacity 10 L
Reserve amount 1.8 L
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8-2
SPECIFICATIONS
8
Carburetor
Manufacturer MIKUNI
Model × quantity TM28SS × 1
Spark plug
Manufacturer/model NGK / BR9ES
NGK / BR8ES (CH, A only)
Spark plug gap 0.7–0.8 mm
Clutch typeWet, multiple-disc
Transmission
Primary reduction system Helical gear
Primary reduction ratio 71/22 (3.227)
Secondary reduction system Chain drive
Secondary reduction ratio 3.563
Number of drive chain
sprocket teeth (rear/front) 57/16
Transmission type Constant mesh 6-speed
Operation Left foot operation
Gear ratio 1st 2.833
2nd 1.875
3rd 1.412
4th 1.143
5th 0.957
6th 0.818Chassis
Frame type Semi double cradle
Caster angle 27°30’
Trail 113 mm
Tire
Front
Type With tube
Size 2.75-21 45P
Manufacturer/ BRIDGESTONE / TW25
model
Rear
Type With tube
Size 4.10-18 59P
Manufacturer/ BRIDGESTONE / TW44
model
Maximum load* 180 kg
178 kg (CH, A only)
Air pressure (cold tire)
up to 90 kg load*
Front125 kPa (1.25 kgf/cm
2, 1.25 bar)
Rear150 kPa (1.50 kgf/cm2, 1.50 bar)
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