Page 7 of 91

PERIODIC MAINTENANCE AND MINOR
REPAIR................................................................6-1
Tool kit..............................................................6-1
Periodic maintenance and lubrication chart......6-3
Cowling removal and installation......................6-6
Cowling A..........................................................6-6
Cowling B..........................................................6-7
Cowling C.........................................................6-8
Panel removal and installation..........................6-8
Panel D.............................................................6-9
Panel E.............................................................6-9
Spark plug.......................................................6-10
Transmission oil..............................................6-11
Cooling system...............................................6-12
Changing the coolant......................................6-13
Air filter............................................................6-15
Carburetor adjustment....................................6-16
Idle speed adjustment.....................................6-17
Throttle cable free play adjustment.................6-17
Tires................................................................6-18
Wheels............................................................6-20
Clutch lever free play adjustment...................6-21
Front brake lever free play adjustment...........6-21
Rear brake pedal height adjustment...............6-22
Brake light switch adjustment.........................6-23
Checking the front and rear brake pads.........6-23Inspecting the brake fluid level.......................6-24
Brake fluid replacement..................................6-25
Drive chain slack check..................................6-25
Drive chain slack adjustment..........................6-26
Drive chain lubrication....................................6-26
Cable inspection and lubrication.....................6-27
Throttle cable and grip lubrication...................6-27
Autolube pump adjustment.............................6-28
Brake and shift pedal lubrication.....................6-28
Brake and clutch lever lubrication...................6-28
Sidestand lubrication......................................6-29
Front fork inspection.......................................6-29
Steering inspection.........................................6-30
Wheel bearings...............................................6-30
Battery............................................................6-31
Fuse replacement...........................................6-33
Headlight bulb replacement............................6-33
Turn signal light bulb replacement..................6-35
Tail/brake light bulb replacement....................6-35
Supporting the motorcycle..............................6-36
Front wheel removal.......................................6-36
Front wheel installation...................................6-37
Rear wheel removal........................................6-38
Rear wheel installation....................................6-39
Troubleshooting..............................................6-39
Troubleshooting chart.....................................6-40
TABLE OF CONTENTS
1
2
3
4
5
6
7
8
9
6
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Page 22 of 91

3-9
INSTRUMENT AND CONTROL FUNCTIONS
1
23
4
5
6
7
8
9
EC000114
cCThe following must be observed to
prevent a fire hazard or other dam-
ages.
8 8
Use only unleaded gasoline.
Use of leaded gasoline will
cause unrepairable damage to
the catalytic converter.
8 8
Never park this motorcycle in
an area that would cause a fire
hazard such as grass or other
materials that may easily burn.
8 8
Do not allow the engine to idle
for very long.
EAU03050
Fuel cockThe fuel cock supplies fuel from the
tank to the carburetor while filtering it
also.
The fuel cock has three positions:
OFF
With the lever in this position, fuel will
not flow. Always return the lever to
this position when the engine is not
running.
RES
ONFUEL
OFF
1
1.Arrow mark positioned ÒOFFÓ
EAU02956
Two-stroke engine oilMake sure there is sufficient two-
stroke engine oil in the oil tank. Add
the recommended oil as necessary.
21
1.Oil tank cap
2.Stopper
Recommended oil:
Yamalube 2 or 2-stroke
engine oil (JASO FC grade or
ISO EG-C, EG-D grade)
Oil quantity:
1.2 L
OFF: closed position
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Page 42 of 91

6-5
PERIODIC MAINTENANCE AND MINOR REPAIR
1
2
3
4
56
7
8
9
EAU03884
NOTE:
8The air filter needs more frequent service if you are riding in unusually wet or dusty areas.
8Hydraulic brake service
9Regularly check and, if necessary, correct the brake fluid level.
9Every two years replace the internal components of the brake master cylinders and calipers, and change the
brake fluid.
9Replace the brake hoses every four years and if cracked or damaged.21
*Carburetor¥Check starter (choke) operation.
¥Adjust engine idling speed.ÖÖÖÖÖÖ
22*Autolube pump¥Check operation.
¥Bleed if necessary.ÖÖÖÖ
23Transmission oil¥Check oil level.ÖÖÖÖÖÖ
¥Change.ÖÖ
24*Cooling system¥Check coolant level and vehicle for coolant leakage.ÖÖÖÖÖ
¥Change.Every 3 years
25*Front and rear brake
switches¥Check operation.ÖÖÖÖÖÖ
26Moving parts and cables¥Lubricate.ÖÖÖÖÖ
27*Lights, signals and
switches¥Check operation.
¥Adjust headlight beam.ÖÖÖÖÖÖ NO.ITEMCHECK OR MAINTENANCE JOBODOMETER READING (´ 1,000 km)
ANNUAL
CHECK
16121824
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PERIODIC MAINTENANCE AND MINOR REPAIR
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2
3
4
56
7
8
96.Insert the air filter guide into the
air filter and install it in the case.
7.Install the air filter case cover
and panel by installing the
screws.
EC000082
cC8
8
Make sure the air filter is prop-
erly seated in the air filter
case.
8 8
The engine should never be
run without the air filter
installed. Excessive piston
and/or cylinder wear may
result.
EAU00629
Carburetor adjustmentThe carburetor is a vital part of the
engine and requires very sophisticat-
ed adjustment. Most adjustments
should be left to a Yamaha dealer
who has the professional knowledge
and experience to do so. However,
the following may be serviced by the
owner as part of routine mainte-
nance.
EC000094
cCThe carburetor was set at the
Yamaha factory after many tests. If
the settings are changed, poor
engine performance and damage
may result.
4.Remove the air filter element
from its guide and clean it with
solvent. After cleaning, remove
the remaining solvent by squeez-
ing the element.
5.Apply recommended oil to the
entire surface of the element and
squeeze out the excess oil. It
should be wet but not dripping.
1
2
1.Guide
2.Filter element
Recommended oil:
Engine oil
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Page 84 of 91
8-1
1
2
3
4
5
6
78
9
EAU01038
SPECIFICATIONS
Specifications
ModelDT125R
Dimensions
Overall length2,170 mm
2,235 mm (N, S, SF, CH, A only)
Overall width830 mm
Overall height1,255 mm
Seat height885 mm
Wheel base1,415 mm
Ground clearance315 mm
Minimum turning radius2,100 mm
Basic weight (with oil and
full fuel tank)127 kg
129 kg (CH, A only)
Engine
Engine typeLiquid-cooled 2-stroke
Cylinder arrangementForward-inclined single
cylinder
Displacement124 cm
3
Bore ´Stroke56.0 ´50.7 mm Compression ratio6.7:1
Starting systemKick starter
Lubrication systemSeparate lubrication
(Yamaha autolube)
Engine oil (2-cycle)
Type2 stroke engine oil
Capacity
Total amount1.2 L
Transmission oil
TypeSAE 10W30 type SE motor oil
Capacity
Periodic oil change0.75 L
Total amount0.8 L
Radiator capacity
(Including all routes)0.92 L
Air filterWet type element
Fuel
TypeRegular unleaded gasoline
Fuel tank capacity10 L
Reserve amount1.8 L
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