Page 28 of 97

INSTRUMENT AND CONTROL FUNCTIONS
3-12
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10
To close the fuel tank cap 1. Push the fuel tank cap into posi- tion with the key inserted in the
lock.
2. Turn the key counterclockwise to the original position, remove it,
and then close the lock cover.
NOTE:
The fuel tank cap cannot be closed
unless the key is in the lock. In addi-
tion, the key cannot be removed if the
cap is not properly closed and locked.
EWA11090
WARNING0
Make sure that the fuel tank cap is
properly closed before riding.
EAU13211
Fuel
1. Fuel tank filler tube
2. Fuel level
Make sure that there is sufficient fuel
in the tank. Fill the fuel tank to the bot-
tom of the filler tube as shown.
EWA10880
WARNING0
• Do not overfill the fuel tank,otherwise it may overflow when
the fuel warms up and expands.
• Avoid spilling fuel on the hot
engine.
ECA10070CAUTION:
Immediately wipe off spilled fuel
with a clean, dry, soft cloth, since
fuel may deteriorate painted sur-
faces or plastic parts.
EAU13390
Recommended fuel: PREMIUM UNLEADED
GASOLINE ONLY
Fuel tank capacity: 23.0 L (6.07 US gal) (5.05 Imp.gal)
Fuel reserve amount (when the fuel
level warning light comes on): 6.7 L (1.77 US gal) (1.47 Imp.gal)
XT660Z 01-03 ING 10-03-2008 16:11 Pagina 3-12
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INSTRUMENT AND CONTROL FUNCTIONS
3-13
EAU13412
Fuel tank breather hose
1. Fuel tank breather hose
2. Clamp
Before operating the motorcycle:
●Check the fuel tank breather hose
connection.
●Check the fuel tank breather hose
for cracks or damage, and replace
it if damaged.
●Make sure that the fuel tank
breather hose is not blocked, and
clean it if necessary.
ECA11400CAUTION:
Use only unleaded gasoline. The
use of leaded gasoline will cause
severe damage to internal engine
parts, such as the valves and piston
rings, as well as to the exhaust sys-
tem.
Your Yamaha engine has been de-
signed to use premium unleaded
gasoline with a research octane num-
ber of 95 or higher. If knocking (or
pinging) occurs, use a gasoline of a
different brand. Use of unleaded fuel
will extend spark plug life and reduce
maintenance costs.
EAU13431
Catalytic converter
This model is equipped with a catalyt-
ic converter in the exhaust system.
EWA10860
WARNING0
The exhaust system is hot after op-
eration. Make sure that the exhaust
system has cooled down before
doing any maintenance work.
XT660Z 01-03 ING 10-03-2008 16:11 Pagina 3-13
Page 30 of 97
INSTRUMENT AND CONTROL FUNCTIONS
3-14
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To install the seat
1. Projections
2. Seat holders
1. Insert the projections on the front of the seat into the seat holders.
2. Push the rear of the seat down.
NOTE:
Make sure that the seat is properly se-
cured before riding.
EAU13870
Seat
To remove the seat
1. Seat lock
2. Unlock
1. Insert the key into the lock, and then turn it counterclockwise.
2. Pull the seat off.
ECA10700CAUTION:
The following precautions must be
observed to prevent a fire hazard or
other damages.
●Use only unleaded gasoline.
The use of leaded gasoline will
cause unrepairable damage to
the catalytic converter.
●Never park the vehicle near
possible fire hazards such as
grass or other materials that
easily burn.
●Do not allow the engine to idle
too long.
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-20
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NOTE:
If the specified clutch lever free play
could be obtained as described above,
tighten the locknut and skip the rest of
the procedure, otherwise proceed as
follows. 3. Fully turn the adjusting bolt at the clutch lever in direction (a) to
loosen the clutch cable.
4. Loosen the locknut at the crankcase.
1. Locknut
2. Clutch lever free play adjusting nut(crankcase)
5. To increase the clutch lever free
play, turn the adjusting nut in di-
rection (a). To decrease the clutch
lever free play, turn the adjusting
nut in direction (b).
6. Tighten the locknut at the clutch lever and the crankcase.
1
b
a
2
EAU22041
Adjusting the clutch lever
free play
1. Locknut
2. Adjusting bolt
3. Clutch lever free play
The clutch lever free play should mea-
sure 10.0-15.0 mm (0.39-0.59 in) as
shown. Periodically check the clutch
lever free play and, if necessary, ad-
just it as follows.1. Loosen the locknut at the clutch lever.
2. To increase the clutch lever free play, turn the adjusting bolt in di-
rection (a). To decrease the clutch
lever free play, turn the adjusting
bolt in direction (b).
31
2
b
a
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-22
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Insufficient brake fluid may allow air to
enter the brake system, possibly caus-
ing it to become ineffective.
Before riding, check that the brake flu-
id is above the minimum level mark
and replenish if necessary.
A low brake fluid level may indicate
worn brake pads and/or brake system
leakage. If the brake fluid level is low,
be sure to check the brake pads for
wear and the brake system for leak-
age.
Observe these precautions:
●When checking the fluid level,
make sure that the top of the
brake fluid reservoir is level.
●Use only the recommended qual-
ity brake fluid, otherwise the rub-
ber seals may deteriorate, caus-
ing leakage and poor braking
performance.
●Refill with the same type of brake
fluid. Mixing fluids may result in a
harmful chemical reaction and
lead to poor braking performance.
●Be careful that water does not en-
ter the brake fluid reservoir when
refilling. Water will significantly
lower the boiling point of the fluid
and may result in vapor lock.
●Brake fluid may deteriorate paint-
ed surfaces or plastic parts. Al-
ways clean up spilled fluid imme-
diately.
●As the brake pads wear, it is nor-
mal for the brake fluid level to
gradually go down. However, if
the brake fluid level goes down
suddenly, have a Yamaha dealer
check the cause.
Recommended brake fluid: DOT 4
EAU22580
Checking the brake fluid
level
Front brake
1. Minimum level mark
Rear brake
1. Minimum level mark
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-24
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1. Wheel axle
2. Drive chain slack adjusting bolt
3. Locknut
4. Alignment marks
ECA10570
CAUTION:
Improper drive chain slack will
overload the engine as well as oth-
er vital parts of the motorcycle and
can lead to chain slippage or break-
age. To prevent this from occurring,
keep the drive chain slack within
the specified limits.
3. Tighten the locknuts, then the axle nut to their specified torques.
Tightening torques:
Locknut:16 Nm (1.6 m·kgf, 11 ft·lbf)
Axle nut: 105 Nm (10.5 m·kgf, 75 ft·lbf)
EAU34311
To adjust the drive chain slack1. Loosen the axle nut and the lock- nut on each side of the swingarm.
2. To tighten the drive chain, turn the adjusting bolt on each side of the
swingarm in direction (a). To
loosen the drive chain, turn the
adjusting bolt on each side of the
swingarm in direction (b), and
then push the rear wheel forward.
NOTE:
Using the alignment marks on each
side of the swingarm, make sure that
both chain pullers are in the same po-
sition for proper wheel alignment.
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PERIODIC MAINTENANCE AND MINOR REPAIR
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ECA10640CAUTION:
Do not use a fuse of a higher am-
perage rating than recommended
to avoid causing extensive damage
to the electrical system and possi-
bly a fire.
3. Turn the key to “ON” and turn on the electrical circuit in question to
check if the device operates.
4. If the fuse immediately blows again, have a Yamaha dealer
check the electrical system.
1. Parking lighting fuse
2. Signaling system fuse
3. Headlight fuse
4. Ignition fuse
5. Electronic fuel injection fuse
6. Radiator fan fuse
7. Backup fuse
8. Reserve fuses
The main fuse and fuse box are locat-
ed under the seat. (See page 6-31.)
If a fuse is blown, replace it as follows.1. Turn the key to “OFF” and turn off the electrical circuit in question.
2. Remove the blown fuse, and then install a new fuse of the specified
amperage.
7
8
654321
Specified fuses:
Main fuse:30 A
Parking lighting fuse: 10 A
Signalling system fuse: 10 A
Headlight fuse: 20 A
Ignition fuse: 10 A
Fuel injection system fuse: 10 A
Radiator fan fuse: 7.5 A
Backup fuse (for odometer,
clock and immobilizer): 10 A
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PERIODIC MAINTENANCE AND MINOR REPAIR
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ECA10650CAUTION:
Take care not to damage the fol-
lowing parts:
●Headlight bulb • Do not touch the glass part
of the headlight bulb to keep
it free from oil, otherwise the
transparency of the glass,
the luminosity of the bulb,
and the bulb life will be ad-
versely affected. Thoroughly
clean off any dirt and finger-
prints on the headlight bulb
using a cloth moistened with
alcohol or thinner.
●Headlight lens
• Do not affix any type of tinted
film or stickers to the head-
light lens.
• Do not use a headlight bulb
of a wattage higher than
specified.
4. Connect the coupler, and then in- stall the headlight bulb cover.
5. Have a Yamaha dealer adjust the headlight beam if necessary.
EAU24180
Tail/brake light
This model is equipped with an LED
type of tail/brake light.
If the tail/brake light does not come on,
have a Yamaha dealer check it.
EAU24202
Replacing a turn signal
light bulb
1. Screw
2. Turn signal light lens
3. Turn signal light bulb
1. Remove the turn signal light lensby removing the screw.
2. Remove the defective bulb by pushing it in and turning it coun-
terclockwise.
3. Insert a new bulb into the socket, push it in, and then turn it clock-
wise until it stops.
4. Install the lens by installing the screw.
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