Page 55 of 97

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PERIODIC MAINTENANCE AND MINOR REPAIR
6-13
NOTE:
The coolant should be between the
minimum and maximum level marks.
1. Coolant reservoir
2. Maximum level mark
3. Minimum level mark
4. Reservoir cap
3. If the coolant is at or below theminimum level mark, remove pan-
el E (See page 6-7.), remove the
reservoir cap, add coolant to the
maximum level mark, and then in-
stall the reservoir cap and the
panel.
ECA10471CAUTION:
● If coolant is not available, use
distilled water or soft tap water
instead. Do not use hard water
or salt water since it is harmful
to the engine.
● If water has been used instead
of coolant, replace it with
coolant as soon as possible,
otherwise the cooling system
will not be protected against
frost and corrosion.
● If water has been added to the
coolant, have a Yamaha dealer
check the antifreeze content of
the coolant as soon as possi-
ble, otherwise the effective-
ness of the coolant will be re-
duced.
Coolant reservoir capacity:
0.50 L (0.52 US qt) (0.44 Imp.qt)
EWA10380
WARNING0
Never attempt to remove the radia-
tor cap when the engine is hot.
NOTE:
●The radiator fan is automatically
switched on or off according to
the coolant temperature in the ra-
diator.
●If the engine overheats, see page
3-4 for further instructions.
EAU33030
Changing the coolant
EWA10380
WARNING0
Never attempt to remove the radia-
tor cap when the engine is hot.
The coolant must be changed at the
intervals specified in the periodic
maintenance and lubrication chart.
Have a Yamaha dealer change the
coolant.
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-32
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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
6-41
Engine overheatingEWA10400
WARNING0
●Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be
blown out under pressure, which could cause serious injury. Be sure to wait until the engine has cooled.
●After removing the radiator cap retaining bolt, place a thick rag, like a towel, over the radiator cap, a\
nd then
slowly rotate the cap counterclockwise to the detent to allow any residual pressure to escape. When the hiss-
ing sound has stopped, press down on the cap while turning it counterclockwise, and then remove the cap.
NOTE:
If coolant is not available, tap water can be temporarily used instead, provided that it is changed to the recommended
coolant as soon as possible.
Wait until the
engine has cooled.Check the coolant level
in the reservoir and radiator.
The coolant level is low.
Check the cooling
system for leakage.
The coolant level
is OK.
There is
leakage.
There is no
leakage.
Have a Yamaha dealer check
and repair the cooling system.
Start the engine. If the engine overheats again, have
a Yamaha dealer check and repair the cooling system.
Add coolant. (See NOTE.)
XT660Z 04-06 ING 11-03-2008 8:31 Pagina 6-41
Page 88 of 97

SPECIFICATIONS
8-1
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10
Engine oil:Type: SAE10W30 or SAE10W40 or SAE15W40
or SAE20W40 or SAE20W50
Recommended engine oil grade: API service SE, SF, SG type or higher
Engine oil quantity: Without oil filter element replacement:2.50 L (2.64 US qt) (2.19 Imp.qt)
With oil filter element replacement: 2.60 L (2.73 US qt) (2.26 Imp.qt)
Total amount (dry engine): 2.90 L (3.07 US qt) (2.55 Imp.qt)
Cooling system:Radiator capacity (including all routes): 1.2 L (1.26 US qt) (1.05 Imp.qt) (Radiator) +
0.5 L (0.52 US qt) (0.44 Imp.qt)
(Coolant reservoir)
Coolant reservoir capacity (up to the
maximum level mark): 0.50 L (0.52 US qt) (0.44 Imp.qt)
From low to full level: 0.30 L (0.32 US qt) (0.26 Imp.qt)
Air filter:Air filter element:Paper
Fuel:Recommended fuel:Premium unleaded gasoline only
Fuel tank capacity: 23.0 L (6.07 US gal) (5.06 Imp.gal)
Fuel reserve amount: 6.7 L (1.76 US gal) (1.46 Imp.gal)
Fuel injection:Manufacturer:DENSO
Model: 297500-0390
Spark plug:Manufacturer/model:NGK/CR7EGap:0.7-0.8 mm (0.028-0.032 in)
Clutch:Clutch type:Wet, multiple-disc
Transmission:Primary reduction system:Spur gear
Primary reduction ratio: 75/36 (2.083)
Secondary reduction system: Chain drive
Secondary reduction ratio: 45/15 (3.00)
Transmission type: Constant mesh 5-speed
Dimensions:Overall length:2246 mm (88.42 in)
Overall width: 864 mm (34.01 in)
Overall height: 1477 mm (58.14 in)
Seat height: 896 mm (35.27 in)
Wheelbase: 1500 mm (59.05 in)
Ground clearance: 260 mm (10.23 in)
Minimum turning radius: 1958 mm (77.08 in)
Basic weight:With oil and fuel:208.5 kg (459 lb)
Engine:Engine type:Liquid cooled 4-stroke, SOHC
Cylinder arrangement: Forward-inclined single cylinder
Displacement: 660.0 cm
3(40.27 cu.in)
Bore x stroke: 100.0 x 84.0 mm (3.94 x 3.31 in)
Compression ratio: 10.00 : 1
Starting system: Electric starter
Lubrication system: Dry sump
-20 -10 0 10 20 30 40 50 °C
SAE 10W-30
SAE 10W-40
SAE 20W-40
SAE 20W-50
SAE 15W-40
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Page 90 of 97

SPECIFICATIONS
8-3
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Rear suspension:
Type: Swingarm (link suspension)
Spring/damper type: Coil spring/gas-oil damper, spring
preload adjustable
Wheel travel: 200 mm (7.87 in)
Electrical system:
Ignition system:Transistorized coil ignition (digital)
Charging system: A.C. magneto
Battery:
Model:GT9B-4
Voltage, capacity: 12 V, 8 Ah
Headlight:
Bulb type:Halogen bulb
Bulb voltage, wattage x quantity:Headlight:12 V, 55 W x 2
Auxiliary light: 12 V, 5 W x 2
Tail/brake light: LED
Front turn signal light: 12 V, 10 W x 2
Rear turn signal light: 12 V, 10 W x 2
Meter lighting: LED (backlight) Neutral indicator light:
LED
Turn signal indicator light: LED
High beam indicator light: LED
Coolant temperature warning light: LED
Engine trouble warning light: LED
Immobilizer system indicator light: LED
Fuses:Main fuse:
30 A
Headlight fuse: 20 A
Signaling system fuse: 10 A
Ignition fuse: 10 A
Parking lighting fuse: 10 A
Radiator fan fuse: 7.5 A
Fuel injection system fuse: 10 A
Backup fuse (for odometer, clock and immobilizer):
10 A
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