2002 YAMAHA TTR90 light

ILLUSTRATED SYMBOLS
(Refer to the illustration)
Illustrated symbols
1
to
6
are designed as
thumb tabs to indicate the chapter’s number
and content.
1
General information
2
Specifications
3
Regular inspection and adjustments
4
Engine
5
Chassis
6
Electrical
Illustrated symbols
7
to
D
are used to identify
the specifications appearing in the text.
7
With engine mounted
8
Special tool
9
Filling fluid
0
Lubricant
A
Tightening
B
Specified value, Service limit
C
Engine speed
DResistance (W), Voltage (V), Electric current (A)
Illustrated symbols E to H in the exploded
diagram indicate grade of lubricant and loca-
tion of lubrication point.
EApply engine oil
FApply molybdenum disulfide oil
GApply lightweight lithium-soap base grease
HApply molybdenum disulfide grease
Illustrated symbols I to J in the exploded
diagrams indicate where to apply a locking
agent and when to install new parts.
IApply locking agent (LOCTITE®)
JUse new one 12
34
56
78
90
AB
CD
E F
G H
IJ
GEN
INFOSPEC
INSP
ADJENG
CHAS–+ELEC
T R..
EM
LSM
LTNew

1 - 1
GEN
INFO
DESCRIPTION
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
1“ENGINE STOP” button
2Front brake lever
3Throttle grip
4Fuel tank cap
5Kick starter
6Fuel tank
7Air cleaner
8Rear brake pedal
9Fuel cock
0Starter lever (choke)
ADrive chain
BShift pedal
CFront fork
NOTE:
lThe machine you have purchased may differ
slightly from those shown in the following.
lDesigns and specifications are subject to
change without notice.
1
1

1 - 4
GEN
INFO
IMPORTANT INFORMATION
EC132000
ALL REPLACEMENT PARTS
1. We recommend to use Yamaha genuine
parts for all replacements. Use oil and/or
grease recommended by Yamaha for
assembly and adjustment.
EC133000
GASKETS, OIL SEALS AND O-RINGS
1. All gaskets, oil seals, and O-rings should
be replaced when an engine is over-
hauled. All gasket surfaces, oil seal lips,
and O-rings must be cleaned.
2. Properly oil all mating parts and bearings
during reassembly. Apply grease to the
oil seal lips.
EC134000
LOCK WASHERS/PLATES AND COTTER
PINS
1. All lock washers/plates 1 and cotter pins
must be replaced when they are
removed. Lock tab(s) should be bent
along the bolt or nut flat(s) after the bolt
or nut has been properly tightened.
EC135001
BEARINGS AND OIL SEALS
1. Install the bearing(s) 1 and oil seal(s) 2
with their manufacturer’s marks or num-
bers facing outward. (In other words, the
stamped letters must be on the side
exposed to view.) When installing oil
seal(s), apply a light coating of light-
weight lithium base grease to the seal
lip(s). Oil the bearings liberally when
installing.
CAUTION:
Do not use compressed air to spin the
bearings dry. This causes damage to the
bearing surfaces.

1 - 9
GEN
INFO
CONTROL FUNCTIONS
EC150000
CONTROL FUNCTIONS
“ENGINE STOP” SWITCH
Make sure that the engine stop switch 1 is
positioned to “ ”. The engine stop switch has
been equipped to ensure safety in an emer-
gency such when the machine is up set or
trouble takes place in the throttle system. The
engine will not start or run when the engine
stop switch is turned to “ ”.
SHIFT PEDAL
The gear ratios of the constant-mesh 3 speed
transmission are ideally spaced. The gears
can be shifted by using the shift pedal 1 on
the left side of the engine.
WARNING
When starting out on the machine, shift the
transmission into 1st after pulling in the
front brake lever and closing the throttle
grip.
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 - 12
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.
1. Turn the fuel cock to “ON”.
2. Operate the starter (choke) and com-
pletely close the throttle grip.
3. Slide the “ENGINE STOP” switch to the
“”.
4. Kick the kick starter with full strength to
start the engine.
5. 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.

3 - 5
INSP
ADJ
ENGINE OIL LEVEL INSPECTION
1. Start the engine, warm it up for several
minutes and wait for five minutes.
2. Place the machine on a level place and
hold it up on upright position by placing
the suitable stand under the engine.
3. Remove:
lDipstick 1
4. Check:
lOil level
Oil level should be between maximum
a and minimum b marks.
Oil level is low ® Add oil to proper
level.
NOTE:
When inspecting the oil level, do not screw the
dipstick into the oil tank. Insert the gauge
lightly.
(For USA and CDN)
CAUTION:
lDo not add any chemical additives.
Engine oil also lubricates the clutch and
additives could cause clutch slippage.
lDo not allow foreign material to enter the
crankcase.
Recommended oil:
At –10 ˚C (10 ˚F) or higher :
Yamalube 4 (10W-30) or SAE
10W-30 type SE/SF motor oil
At 5 ˚C (40 ˚F) or higher õ:
Yamalube 4 (20W-40) or SAE
20W-40 type SE/SF motor oil010 30 50 70
90110
130
-20
-10010
20 30 40
50

õ
˚C˚F
ENGINE OIL LEVEL INSPECTION

3 - 7
INSP
ADJ
PILOT AIR SCREW ADJUSTMENT
5. Install:
lGasket
lDrain bolt
New
T R..20 Nm (2.0 m · kg, 14 ft · lb)
6. Fill:
lCrankcase
Oil quantity:
Periodic oil change:
0.8 L (0.70 Imp qt, 0.85 US qt)
7. Install:
lDipstick
8. Inspect:
lEngine (for oil leaks)
lOil level
Refer to “ENGINE OIL LEVEL INSPEC-
TION”.
PILOT AIR SCREW ADJUSTMENT
1. Adjust:
lPilot air screw 1
Adjusting steps:
lScrew in the pilot air screw until it is lightly
seated.
lBack out by the specified number of turns.
Pilot air screw:
1-3/4 turns out

3 - 10
INSP
ADJ
SPARK ARRESTER CLEANING (For USA)
6. Install:
lTappet cover (intake side) 1
lO-ring 2
7. Install:
lTappet cover (exhaust side)
lO-ring
lSpark plug
lTiming plug
lCrankshaft end cover
8. Install:
lAir filter case
lAir scoop (right)
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)
SPARK ARRESTER CLEANING (For USA)
WARNING
lBe sure the exhaust pipe and muffler are
cool before cleaning the spark arrester.
lDo not start the engine when cleaning the
exhaust system.
1. Remove:
lBolt (tailpipe) 1
2. Remove:
lTailpipe 2
Pull the tailpipe out of the muffler.
3. Clean:
lSpark 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:
lTailpipe
Insert the tailpipe into the muffler and
align the bolt hole.
lBolt (tailpipe)
2
1
3
a
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)