Page 34 of 91

5-3
OPERATION AND IMPORTANT RIDING POINTS
1
2
3
45
6
7
8
9 1.Turn the fuel cock to ÒONÓ.
2.Turn the main switch to ÒONÓ and
the engine stop switch to Ò#Ó.
3.Shift the transmission into neu-
tral.
NOTE:
When the transmission is in neutral,
the neutral indicator light should be
on. If the light does not come on, ask
a Yamaha dealer to inspect it.4.Turn on the starter (choke) and
completely close the throttle grip.
5.Kick the kick starter to start the
engine.
6.After starting the engine, move
the starter (choke) to the halfway
position.
NOTE:
For maximum engine life, never
accelerate hard with a cold engine!7.After the engine is warm, turn off
the starter (choke) completely.NOTE:
The engine is warm when it responds
normally to the throttle with the starter
(choke) turned off.
EAU01258
Starting a warm engineThe starter (choke) is not required
when the engine is warm.
EC000046
cCSee the ÒEngine break-inÓ section
prior to operating the motorcycle
for the first time.
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5-4
OPERATION AND IMPORTANT RIDING POINTS
1
2
3
45
6
7
8
9
EAU00423
ShiftingThe transmission lets you control the
amount of power you have available
at a given speed for starting, acceler-
ating, climbing hills, etc. The use of
the shift pedal is shown in the illustra-
tion.
To shift into neutral, depress the shift
pedal repeatedly until it reaches the
end of its travel, then raise the pedal
slightly.
EC000048
cC8
8
Do not coast for long periods
with the engine off, and do not
tow the motorcycle a long dis-
tance. Even with gears in neu-
tral, the transmission is only
properly lubricated when the
engine is running. Inadequate
lubrication may damage the
transmission.
8 8
Always use the clutch when
changing gears. The engine,
transmission, and driveline are
not designed to withstand the
shock of forced shifting and
can be damaged by shifting
without using the clutch.
6
5
4
3
2
1 N
1
N.Neutral
1.Shift pedal
EAU02937
Recommended shift points
(for Switzerland only)The recommended shift points are
shown in the table below.
Acceleration shift point
km/h
1st ®2nd20
2nd ®3rd30
3rd ®4th40
4th ®5th50
5th ®6th60
NOTE:
When shifting two gears down from
5th to 3rd, bring your motorcycle to a
speed of 35 km/h.
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Page 36 of 91

5-5
OPERATION AND IMPORTANT RIDING POINTS
1
2
3
45
6
7
8
9
EAU00424
Tips for reducing fuel
consumptionYour motorcycleÕs fuel consumption
depends to a large extent on your rid-
ing style. The following tips can help
reduce fuel consumption:
8Warm up the engine before rid-
ing.
8Turn off the starter (choke) as
soon as possible.
8Shift up swiftly and avoid high
engine speeds during accelera-
tion.
8Do not double-clutch or rev the
engine while shifting down and
avoid high engine speeds with
no load on the engine.
8Turn off the engine instead of let-
ting it idle for an extended length
of time, i.e. in traffic jams, at traf-
fic lights or railroad crossings.
EAU00436
Engine break-inThere is never a more important peri-
od in the life of your motorcycle than
the period between zero and 1,000
km. For this reason we ask that you
carefully read the following material.
Because the engine is brand new,
you must not put an excessive load
on it for the first 1,000 km. The vari-
ous parts in the engine wear and pol-
ish themselves to the correct operat-
ing clearances. During this period,
prolonged full throttle operation, or
any condition which might result in
excessive heating of the engine,
must be avoided.
EAU00453
0 ~ 500 km
Avoid operation above 6,000 r/min.
Stop the engine and let it cool for 5 to
10 minutes after every hour of opera-
tion. Vary the speed of the motorcy-
cle from time to time. Do not operate
it at one set throttle position.
500 ~ 1,000 km
Avoid prolonged operation above
7,000 r/min. Rev the motorcycle
freely through the gears, but do not
use full throttle at any time.
EC000060
cCAfter 1,000 km of operation, be
sure to replace the transmission
oil.
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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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6-11
PERIODIC MAINTENANCE AND MINOR REPAIR
1
2
3
4
56
7
8
9 Spark plug gap:
0.7 ~ 0.8 mm
Tightening torque:
Spark plug:
20 Nm (2.0 m
0kg)
1
3 2
EAU03109
Transmission oilOil level inspection
1.Place the motorcycle on a level
place and hold it in an upright
position. Warm up the engine for
several minutes.NOTE:
Be sure the motorcycle is positioned
straight up when checking the oil
level. A slight tilt toward the side can
result in false readings.1.Level window
2.Maximum level
3.Minimum level
Installation
1.Measure the electrode gap with
a wire thickness gauge and, if
necessary, adjust the gap to
specification.
2.Clean the gasket surface. Wipe
off any grime from the threads.
3.Install the spark plug and tighten
it to the specified torque.
1
1.Spark plug gap
NOTE:
If a torque wrench is not available
when you are installing a spark plug,
a good estimate of the correct torque
is 1/4 to 1/2 turn past finger tight.
Have the spark plug tightened to the
specified torque as soon as possible.4.Install the spark plug cap.
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6-12
PERIODIC MAINTENANCE AND MINOR REPAIR
1
2
3
4
56
7
8
95.Fill the engine with sufficient oil
to reach the specified level.
Install the oil filler cap and tight-
en it.
EC000079
cCDo not put in any chemical addi-
tives. Transmission oil also lubri-
cates the clutch and additives
could cause clutch slippage.6.Start the engine and warm up for
a few minutes. While warming
up, check for oil leakage. If oil
leakage is found, stop the engine
immediately and check for
cause. Recommended oil:
See page 8-1.
Oil quantity:
Total amount: 0.8 L
Periodic oil change: 0.75 L
1
Transmission oil replacement
1.Warm up the engine for several
minutes.
2.Stop the engine. Place an oil pan
under the engine to catch the oil
and remove the oil filler cap.
3.Remove the drain bolt and drain
the oil.
4.Install the drain bolt and tighten it
to the specified torque.1.Drain bolt
Tightening torque:
Drain bolt:
15 Nm (1.5 m
0kg)
1
2.With the engine stopped, check
the oil level through the level
window located at the right side
crankcase cover.NOTE:
Wait a few minutes until the oil level
settles before checking.3.The oil level should be between
the maximum and minimum level
on the level window. If the level
is low, add sufficient oil to raise it
to the specified level.1.Oil filler cap
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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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SPECIFICATIONS
8-2
1
2
3
4
5
6
78
9
Carburetor
Type ´ quantityTM28SS ´ 1
ManufacturerMIKUNI
Spark plug
Manufacturer / typeNGK / BR9ES
NGK / BR8ES (CH, A only)
Spark plug gap0.7 ~ 0.8 mm
Clutch typeWet, multiple-disc
Transmission
Primary reduction systemHelical gear
Primary reduction ratio71/22 (3.227)
Secondary reduction systemChain drive
Secondary reduction ratio57/16 (3.563)
Transmission typeConstant mesh 6-speed
OperationLeft foot operation
Gear ratio1st2.833
2nd1.875
3rd1.412
4th1.143
5th0.957
6th0.818Chassis
Frame typeSemi double cradle
Caster angle27¡30Õ
Trail113 mm
Tire
TypeWith tube
Front
Size2.75-21 45P
Manufacturer/BRIDGESTONE / TW25
model
Rear
Size4.10-18 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 kg/cm
2, 1.25 bar)
Rear150 kPa (1.50 kg/cm2, 1.50 bar)
3MB-9-E7 12/27/00 2:52 PM Page 84