warning light YAMAHA TTR90 2003 Owners Manual

1 - 10
GEN
INFO
CONTROL FUNCTIONS
KICK STARTER
WARNING
Before starting the engine, be sure to shift
the transmission into neutral.
Rotate the kick starter 1 away from the
engine. Push the starter down lightly with your
foot until the gears engage, then kick smoothly
and forcefully to start the engine.
EC155001
THROTTLE GRIP
The throttle grip 1 is located on the right han-
dlebar; it accelerates or decelerates the
engine. For acceleration, turn the grip toward
you; for deceleration, turn it away from you.
1
EC156000
FRONT BRAKE LEVER
The front brake lever 1 is located on the right
handlebar. Pull it toward the handlebar to acti-
vate the front brake.
1
EC157000
REAR BRAKE PEDAL
The rear brake pedal 1 is located on the right
side of the machine. Press down on the brake
pedal to activate the rear brake.

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GEN
INFO
STARTING AND OPERATION
STARTING AND OPERATION
CAUTION:
Prior to operating the machine, perform
steps listed in pre-operation check list.
WARNING
Never start your engine or let it run for any
length of time in a closed area. The exhaust
fumes are poisonous and can cause loss of
consciousness and death within a short
time. Always operate your machine in an
area with adequate ventilation.
STARTING A COLD ENGINE
WARNING
Before starting the engine, be sure to shift
the transmission into neutral.
NOTE:
This model is equipped with an ignition cir-
cuit cut-off system. In case of electric start-
ing, the engine can be started only when the
transmission is in neutral.
If the engine fails to start by pushing the start
switch, release the switch, wait a few sec-
onds, and then try again. Each starting
attempt should be as short as possible to
preserve the battery. Do not crank the
engine more than 10 seconds on any one
attempt. If the engine does not start with the
starter motor, try using the kickstarter.
1. Turn the fuel cock to “ON”.
2. Turn the main switch to “ON”.
3. Shift the transmission into neutral.
4. Operate the starter (choke) and com-
pletely close the throttle grip.
5. Start the engine by pushing the start
switch or by kicking the kickstarter.
6. After the engine starts, warm up for one
or two minutes. Make sure the stater
(choke) is returned to the original position
before riding.STARTING A WARM ENGINE
To start a warm engine, refer to the “Starting a
cold engine” section. The starter (choke)
should not be used. The throttle should be
opened slightly.
CAUTION:
See “Engine break-in Section” prior to
operating engine for the first time.
WARMING UP
To get maximum engine life, always “warm-up”
the engine before starting off. Never acceler-
ate hard with a cold engine! To see whether or
not the engine is warm, see if it responds to
throttle normally with the stater (choke) turned
off.
WARNING
Before starting off, be sure to turn up or
remove the side stand.
Failure to retract the side stand completely
can result in a serious accident when you
try to turn a corner.
ENGINE BREAK-IN
Brake-in is important to better fit the moving
and sliding parts as well as the installed parts.
It is also important to accustom the rider to the
machine better.
Avoid full-throttle run on a new machine for the
first 5 hours.
After the trial run, check for loose parts, oil
leakage and other problems.
Make full inspection and adjustment especially
of slack cables and drive chain and loose
spokes.
CAUTION:
After the break-in period, check every fit-
ting and fastener for looseness.
If any loose is found, retighten it securely.

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INSP
ADJ
SPARK ARRESTER CLEANING (For USA)
6. Install:
Tappet cover (intake side) 1
O-ring 2
NOTE:
Apply the lithium soap base grease on the O-ring.
7. Install:
Tappet cover (exhaust side)
O-ring
Spark plug
Timing plug
Crankshaft end cover
NOTE:
Apply the lithium soap base grease on the O-ring.
8. Install:
Air filter case
Air scoop (right)
SPARK ARRESTER CLEANING (For USA)
WARNING
Be sure the exhaust pipe and muffler are
cool before cleaning the spark arrester.
Do not start the engine when cleaning the
exhaust system.
1. Remove:
Bolt (tailpipe) 1
2. Remove:
Tailpipe 2
Pull the tailpipe out of the muffler.
3. Clean:
Spark arrester
Use a wire brush to remove any carbon
deposits from the spark arrester portion
of the muffler body 3 inner surface.
Tap the tailpipe lightly and remove the
carbon deposits from the outside por-
tion a of the tailpipe.
4. Install:
Tailpipe
Insert the tailpipe into the muffler and
align the bolt hole.
Bolt (tailpipe)
T R..18 Nm (1.8 m · kg, 13 ft · lb)
New
T R..18 Nm (1.8 m · kg, 13 ft · lb)
New
T R..13 Nm (1.3 m · kg, 9.4 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
2
1
3
a
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)

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INSP
ADJ
BATTERY INSPECTION AND CHARGING
WARNING
Batteries generate explosive hydrogen gas
and contain electrolyte which is made of
poisonous and highly caustic sulfuric acid.
Therefore, always follow these preventive
measures:
Wear protective eye gear when handling
or working near batteries.
Charge batteries in a well-ventilated area.
Keep batteries away from fire, sparks or
open flames (e.g., welding equipment,
lighted cigarettes).
DO NOT SMOKE when charging or han-
dling batteries.
KEEP BATTERIES AND ELECTROLYTE
OUT OF REACH OF CHILDREN.
Avoid bodily contact with electrolyte as it
can cause severe burns or permanent eye
injury.
FIRST AID IN CASE OF BODILY CONTACT:
EXTERNAL
Skin — Wash with water.
Eyes — Flush with water for 15 minutes
and get immediate medical attention.
INTERNAL
Drink large quantities of water or milk fol-
lowed with milk of magnesia, beaten egg
or vegetable oil. Get immediate medical
attention.
CAUTION:
Charging time, charging amperage and
charging voltage for an MF battery are dif-
ferent from those of conventional batteries.
The MF battery should be charged as
explained in the charging method illustra-
tions. If the battery is overcharged, the
electrolyte level will drop considerably.
Therefore, take special care when charging
the battery.
BATTERY INSPECTION AND CHARGING

4 - 6
ENGCARBURETOR
EC464600
Float
1. Inspect:
Float 1
Damage → Replace.
ASSEMBLY AND INSTALLATION
Carburetor
1. Install:
Pilot air screw 1
Note the following installation points:
Screw in the pilot air screw until it is lightly
seated.
Back out it by the specified number of
turns.
Pilot air screw:
1-3/4 turns out
2. Install:
Throttle valve 1
Starter plunger 2
NOTE:
Align the slit a of the throttle valve with the tab
b of the carburetor top.
FUEL LEVEL ADJUSTMENT
WARNING
Gasoline (fuel) and its vapors are highly
flammable and explosive. Keep away from
sparks, cigarettes, flames or other sources
of ignition.

6 - 18
–+ELECCARBURETOR HEATING SYSTEM
WARNING
Handle the thermo switch with special
care.
Never subject the thermo switch to
strong shocks. If the thermo switch is
dropped, replace it.
Check the thermo switch operation.
CARBURETOR HEATER INSPECTION
1. Inspect:
Carburetor heater resistance
Out of specification → Replace.
Tester (+) probe →
Carburetor heater terminal 1
Tester (–) probe →
Carburetor heater body 2
Carburetor
heater resistanceTester selector
position
6 ~ 10 Ω at
20 ˚C (68 ˚F)Ω × 1
CDI MAGNETO INSPECTION
1. Inspect:
Lighting coil resistance
Out of specification → Replace.
Tester (+) lead → Yellow lead 1
Tester (–) lead → Black lead 2
Lighting coil
resistanceTester selector
position
0.52 ~ 0.78 Ω at
20 ˚C (68 ˚F)Ω × 1
WSb
YB
1
2