light YAMAHA TTR90 2000 Owners Manual

EC085001
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 I in the exploded
diagram indicate grade of lubricant and loca-
tion of lubrication point.
EApply gear oil
FApply engine oil
GApply molybdenum disulfide oil
HApply lightweight lithium-soap base grease
IApply molybdenum disulfide grease
Illustrated symbols J to K in the exploded
diagrams indicate where to apply a locking
agent J and when to install a new part K.
JApply locking agent (LOCTITE®)
KReplace 12
34
56
78
90
AB
CD
EFG
HIJ
K
GEN
INFOSPEC
INSP
ADJENG
CHAS–+ELEC
T R..
GME
MLTLS
New

1 - 1
GEN
INFO

DESCRIPTION
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
1
“ENGINE STOP” button
2
Front brake lever
3
Throttle grip
4
Fuel tank cap
5
Kick starter
6
Fuel tank
7
Air cleaner
8
Rear brake pedal
9
Fuel cock
0
Starter lever (choke)
A
Drive chain
B
Shift pedal
C
Front fork
NOTE:

l
The machine you have purchased may differ
slightly from those shown in the following.
l
Designs and specifications are subject to
change without notice.
1
1

1 - 4
GEN
INFO

IMPORTANT INFORMATION
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.
EC136000
CIRCLIPS
1. All circlips should be inspected carefully
before reassembly. Always replace pis-
ton pin clips after one use. Replace dis-
torted circlips. When installing a circlip
1
, make sure that the sharp-edged cor-
ner
2
is positioned opposite to the thrust
3
it receives. See the sectional view.
4
Shaft

1 - 9
GEN
INFO
CONTROL FUNCTIONS
EC150000
CONTROL FUNCTIONS
EC151000
“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 “ ”.
EC153000
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.
EC154000
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.
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.

GEN
INFO
1 - 12
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 “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
1. Prior to starting, fill fuel tank with gasoline
and oil tank with specified oil.
2. Allow engine to warm up. Check engine
idling speed. Check operating controls
and engine stop switch operation.
3. Operate machine in lower gears at mod-
erate throttle setting for 3 ~ 5 minutes.
Check spark plug condition.
4. Allow engine to cool. Repeat procedure,
running for 5 minutes. Very briefly, shift to
higher gears and check full throttle
response. Check spark plug condition.
5. Allow engine to cool. Repeat procedure,
running for 5 minutes. Full throttle and
higher gears may be used, but avoid sus-
tained full throttle operation. Check spark
plug condition.
6. Allow engine to cool. Remove top end and
inspect. Remove “high” spots on piston
with No.600 grit, wet sandpaper.
Clean, and carefully reassemble.
7. Check entire unit for loose or misadjusted
fittings/controls/fasteners.
8. Re-start engine and check through entire
operating range thoroughly. Stop. Check
spark plug condition. Re-start. After 10 ~
15 minutes operation, machine is ready
to ride.
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. Stand the motorcycle on a level surface.
NOTE:

l
When checking the oil level make sure that
the motorcycle is upright.
l
Place the motorcycle on a suitable stand.
WARNING

Never remove the oil tank cap just after
high speed operation. The heated oil could
spurt out causing danger. Wait until the oil
cools down to approximately 70 ˚C (158 ˚F).
2. Idle the engine more than 3 minutes
while keeping the motorcycle upright.
Then stop the engine and inspect the oil
level.
3. Remove:
l
Dipstick
1
4. Inspect:
l
Oil 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
oil level gauge into the oil tank.
Insert the gauge lightly.
(For USA and CDN)
CAUTION:

l
Do not add any chemical additives.
Engine oil also lubricates the clutch and
additives could cause clutch slippage.
l
Do not allow foreign material to enter the
crankcase.
Recommended oil:
At –10 ˚C (10 ˚F) or higher

:
Yamalube 4 (10W30) or SAE
10W30 type SE/SF motor oil
At 5 ˚C (40 ˚F) or higher
õ
:
Yamalube 4 (20W40) or SAE
20W40 type SE/SF motor oil
010 30 50 70
90110
130
-20
-10 010
20 30 40
50

õ
˚C˚F

ENGINE OIL LEVEL INSPECTION

3 - 7
INSP
ADJ
PILOT AIR SCREW ADJUSTMENT
4. Install:
lGasket
lDrain bolt
New
T R..20 Nm (2.0 m · kg, 14 ft · lb)
5. Fill:
lCrankcase
Oil quantity:
Total amount:
1.0 L (0.88 Imp qt, 1.06 US qt)
Periodic oil change:
0.8 L (0.70 Imp qt, 0.85 US qt)
6. Install:
lDipstick
7. 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 - 18
INSP
ADJ
LUBRICATION
EC36a041
LUBRICATION
To ensure smooth operation of all compo-
nents, lubricate your machine during setup,
after break-in, and after every race.
1All control cable
2Brake lever pivot
3Shift pedal pivot
4Footrest pivot
5Throttle-to-handlebar contact
6Drive chain
7Tube guide cable winding portion
8Throttle cable end
9Brake cable endUse Yamaha cable lube or equivalent on these
areas.
õUse SAE 10W30 motor oil or suitable chain
lubricants.
‚Lubricate the following areas with high quality,
lightweight lithium-soap base grease.
AAA
AAB
CC
78

3 - 19
INSP
ADJ
ELECTRICAL/SPARK PLUG INSPECTION
EC370000
ELECTRICAL
EC371001
SPARK PLUG INSPECTION
1. Remove:
lSpark plug
2. Inspect:
lElectrode 1
Wear/damage ® Replace.
lInsulator color 2
Normal condition is a medium to light
tan color.
Distinctly different color ® Check the
engine condition.
NOTE:
When the engine runs for many hours at low
speeds, the spark plug insulator will become
sooty, even if the engine and carburetor are in
good operating condition.
3. Measure:
lPlug gap a
Use a wire gauge or thickness gauge.
Out of specification ® Regap.
4. Clean the plug with a spark plug cleaner
if necessary.
Spark plug gap:
0.6 ~ 0.7 mm (0.02 ~ 0.03 in)
Standard spark plug:
CR6HSA (NGK)
U20FSR-U (DENSO)
5. Tighten:
lSpark plug
NOTE:
lBefore installing a spark plug, clean the gas-
ket surface and plug surface.
lFinger-tighten a the spark plug before
torquing to specification b.
T R..13 Nm (1.3 m · kg, 9.4 ft · lb)

4 - 6
ENGCARBURETOR
EC464600
Float
1. Inspect:
lFloat 1
Damage ® Replace.
ASSEMBLY AND INSTALLATION
Carburetor
1. Install:
lPilot air screw 1
Note the following installation points:
lScrew in the pilot air screw until it is lightly
seated.
lBack out it by the specified number of
turns.
Pilot air screw:
1-3/4 turns out
2. Install:
lThrottle valve 1
lStarter 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.