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
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3
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5
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7
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6-22
PERIODIC MAINTENANCE AND MINOR REPAIR
1
2
3
4
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7
8
9
EW000099
w8 8
Check the brake lever free
play. Be sure the brake is
working properly.
8 8
A soft or spongy feeling in the
brake lever can indicate the
presence of air in the brake
system. This air must be
removed by bleeding the brake
system before the motorcycle
is operated.  Air in the system
will cause greatly diminished
braking capability and can
result in loss of control and an
accident. Have a Yamaha deal-
er inspect and bleed the sys-
tem if necessary.
a
1
EAU00712
Rear brake pedal height
adjustmentThe top of the brake pedal should be
positioned 15 mm below the top of
the footrest. If not, ask a Yamaha
dealer to adjust it.1.Footrest
a.Pedal height
EW000109
wA soft or spongy feeling in the
brake pedal can indicate the pres-
ence of air in the brake system.
This air must be removed by
bleeding the brake system before
the motorcycle is operated. Air in
the system will cause greatly
diminished braking capability and
can result in loss of control and an
accident. Have a Yamaha dealer
inspect and bleed the system if
necessary.
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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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