warning YAMAHA TTR90 2003 User Guide

3 - 20
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

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INSP
ADJ
BATTERY INSPECTION AND CHARGING
5. Charge:
Battery
(refer to the appropriate charging
method illustration)
WARNING
Do not quick charge a battery.
CAUTION:
Never remove the MF battery sealing
caps.
Do not use a high-rate battery charger
since it forces a high-amperage current
into the battery quickly and can cause
battery overheating and battery plate
damage.
If it is impossible to regulate the charging
current on the battery charger, be careful
not to overcharge the battery.
When charging a battery, be sure to
remove it from the machine. (If charging
has to be done with the battery mounted
on the machine, disconnect the negative
battery lead from the battery terminal.)
To reduce the chance of sparks, do not
plug in the battery charger until the bat-
tery charger leads are connected to the
battery.
Before removing the battery charger lead
clips from the battery terminals, be sure
to turn off the battery charger.
Make sure the battery charger lead clips
are in full contact with the battery termi-
nal and that they are not shorted. A cor-
roded battery charger lead clip may
generate heat in the contact area and a
weak clip spring may cause sparks.
If the battery becomes hot to the touch at
any time during the charging process,
disconnect the battery charger and let the
battery cool before reconnecting it. Hot
batteries can explode!
As shown in the following illustration, the
open-circuit voltage of an MF battery sta-
bilizes about 30 minutes after charging
has been completed. Therefore, wait 30
minutes after charging is completed
before measuring the open-circuit volt-
age.

3 - 26
INSP
ADJ
FUSE INSPECTION
3. Replace:
Blown fuse
WARNING
Never use a fuse with an amperage rating
other than that specified. Improvising or
using a fuse with the wrong amperage rat-
ing may cause extensive damage to the
electrical system, cause the starting and
ignition systems to malfunction and could
possibly cause a fire.
4. Install:
Rear fender
Seat Replacement steps:
Set the main switch to “OFF”.
Install a new fuse of the correct amperage.
Set on the switches to verify if the electri-
cal circuit is operational.
If the fuse immediately blows again, check
the electrical circuit.
ItemsAmperage
ratingQ’ty
Main fuse 10 A 1

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.

5 - 1
CHAS

EC500000
CHASSIS
FRONT WHEEL AND REAR WHEEL
FRONT WHEEL AND FRONT BRAKE
FRONT WHEEL AND REAR WHEEL
Extent of removal:
1
Front wheel removal
2
Wheel bearing removal
3
Brake shoe plate assembly removal and disassembly
Extent of removal Order Part name Q’ty Remarks
FRONT WHEEL REMOVAL
WARNING

Support the machine securely so there is no
danger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
1 Bolt (brake cable holder) 1 Only loosening.
2 Brake cable 1 Disconnect at the lever side.
3 Wheel axle nut 1
4 Front wheel axle 1
5 Front wheel 1
6 Collar set 1
7 Brake shoe plate assembly 1
8 Oil seal 1
9Bearing
2Refer to “REMOVAL POINTS”.
2
31
3

5 - 3
CHAS

FRONT WHEEL AND REAR WHEEL
REAR WHEEL AND REAR BRAKE
Extent of removal:
1
Rear wheel removal
2
Wheel bearing removal
3
Brake shoe plate assembly removal and disassembly
Extent of removal Order Part name Q’ty Remarks
REAR WHEEL REMOVAL
WARNING

Support the machine securely so there is no
danger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
1 Brake rod 1
2 Cotter pin 1
3 Nut (tension bar) 1
4 Bolt (tension bar) 1
5 Wheel axle nut 1
6 Rear wheel axle 1
7 Drive chain puller 2
8 Rear wheel 1
9 Collar (right) 1
10 Brake shoe plate assembly 1
231

5 - 6
CHAS

FRONT FORK
EC550000
FRONT FORK
Extent of removal:
1
Front fork removal
Extent of removal Order Part name Q’ty Remarks
FRONT FORK REMOVAL
WARNING

Support the machine securely so there is no
danger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Front wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Handlebar Refer to “HANDLEBAR” section.
Front fender
1 Brake cable holder 1
2 Cap bolt 1
3 Adjuster 1 Only loosening.
4 Pinch bolt (under bracket) 1 Only loosening.
5 Front fork 1
1

5 - 10
CHASSTEERING
EC560000
STEERING
LS
LS
T R..TIGHTENING STEPS:
•Tighten ring nut.
38 Nm (3.8 m • kg, 27 ft • Ib)
•Loosen it completely.
•Retighten it.
1 Nm (0.1 m • kg, 0.7 ft • Ib)
T R..40 Nm (4.0 m • kg, 29 ft • Ib)
5 9681076 43
21
Extent of removal:1 Under bracket removal2 Bearing removal
Extent of removal Order Part name Q’ty Remarks
STEERING REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Front fork Refer to “FRONT FORK” section.
1 Steering stem bolt 1
2 Handle crown 1
3 Ring nut 1 Use special tool.
Refer to “STEERING HEAD INSPEC-
TION AND ADJUSTMENT” section in
the CHAPTER 3.
4 Ball race cover 1
5 Under bracket 1
6 Bearing inner race 2
7 Upper bearing ball 19
8 Lower bearing ball 16
9 Dust seal 1
10 Bearing outer race 2
2
1

5 - 11
CHASSWINGARM
EC570000
SWINGARM
Extent of removal:1 Swingarm removal2 Rear shock absorber removal
Extent of removal Order Part name Q’ty Remarks
SWINGARM REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Rear wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Rear fender
Drive chain
1 Cotter pin 2
2 Pin 2
3 Rear shock absorber 1
4 Pivot shaft 1 Hold the swingarm.
5 Swing arm 1
6 Drive chain guide 1
7 Drive chain guard 1
8 Drive chain support 1
1
2

6 - 8
–+ELEC
EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:
Couplers and leads connection
Rust/dust/looseness/short-circuit →
Repair or replace.
STARTER MOTOR OPERATION
1. Connect the positive battery terminal 1
and starter motor lead 2 with a jumper
lead 3.
Not operate → Repair or replace the
starter motor.
WARNING
A wire that is used as a jumper lead must
have at least the same capacity or more
as that of the a battery lead, otherwise the
jumper lead may burn.
This check is likely to produce sparks,
therefore make sure nothing flammable is
in the vicinity.
STARTING CIRCUIT CUT-OFF RELAY
INSPECTION
1. Remove:
Starting circuit cut-off relay
2. Inspect:
Starting circuit cut-off relay conduct
Use 12 V battery.
Battery (+) lead → Red/White lead 1
Battery (–) lead → Sky blue lead 2
Tester (+) lead → Red/White lead 3
Tester (–) lead → Red/White lead 4
R/W
3R/W
4Tester selec-
tor position
Connected
to battery
Ω × 1Not
connected
to battery
2 4
3
1
ELECTRIC STARTING SYSTEM