Page 51 of 92

PERIODIC MAINTENANCE AND MINOR REPAIR
6-13
6 addition, do not use oils labeled
“ENERGY CONSERVING II” or
higher.
Make sure that no foreign mate-rial enters the crankcase.
12. Start the engine, and then let it idle
for several minutes while checking
it for oil leakage. If oil is leaking, im-
mediately turn the engine off and
check for the cause.
13. Turn the engine off, and then
check the oil level and correct it if
necessary.
EAU20070
Coolant The coolant level should be checked
before each ride. In addition, the cool-
ant must be changed at the intervals
specified in the periodic maintenance
and lubrication chart.
EAUM1722
To check the coolant level
1. Place the vehicle on a level sur-
face and hold it in an upright posi-
tion.NOTE:
The coolant level must be checked
on a cold engine since the level
varies with engine temperature.
Make sure that the vehicle is posi-
tioned straight up when checking
the coolant level. A slight tilt to theside can result in a false reading.
2. Check the coolant level in the cool-
ant reservoir.
NOTE:The coolant should be between theminimum and maximum level marks.3. If the coolant is at or below the
minimum level mark, remove cowl-
ing B (See page 6-5.), and then
open the reservoir cap.
4. Add coolant to the maximum level
mark, and then close the reservoir
cap.
1. Coolant reservoir
2. Maximum level mark
3. Minimum level mark
Coolant reservoir capacity (up to the
maximum level mark):
0.25 L (0.26 US qt) (0.22 Imp.qt)
U5VKE1E0.book Page 13 Tuesday, July 18, 2006 1:00 PM
Page 53 of 92

PERIODIC MAINTENANCE AND MINOR REPAIR
6-15
6 9. Remove the coolant drain bolt to
drain the cooling system.
10. After the coolant is completely
drained, thoroughly flush the cool-
ing system with clean tap water.11. Install the coolant drain bolt, and
then tighten it to the specified
torque.
NOTE:Check the washer for damage and re-place it if necessary.
12. Pour the specified amount of the
recommended coolant into the ra-
diator and reservoir.
CAUTION:
ECA10471
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 cool-
ant as soon as possible, other-
wise 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 possible,
otherwise the effectiveness ofthe coolant will be reduced.
13. Install the coolant reservoir cap.
14. Install the radiator cap and radiator
cap retainer by installing the
screw.
15. Start the engine, let it idle for sev-
eral minutes, and then turn it off.
1. Bolt
1. Coolant drain bolt
Tightening torque:
Coolant drain bolt:
11 Nm (1.1 m·kgf, 8.0 ft·lbf)
Antifreeze/water mixture ratio:
1:1
Recommended antifreeze:
High-quality ethylene glycol anti-
freeze containing corrosion inhibitors
for aluminum engines
Coolant quantity:
Radiator capacity (including all
routes):
1.00 L (1.06 US qt) (0.88 Imp.qt)
Coolant reservoir capacity (up to the
maximum level mark):
0.25 L (0.26 US qt) (0.22 Imp.qt)
U5VKE1E0.book Page 15 Tuesday, July 18, 2006 1:00 PM
Page 84 of 92

SPECIFICATIONS
8-1
8
Dimensions:Overall length:
XT660R 2240 mm (88.2 in)
XT660X 2175 mm (85.6 in)
Overall width:
XT660R 845 mm (33.3 in)
XT660X 860 mm (33.9 in)
Overall height:
XT660R 1230 mm (48.4 in)
XT660X 1170 mm (46.1 in)
Seat height:
XT660R 865 mm (34.1 in)
XT660X 875 mm (34.4 in)
Wheelbase:
XT660R 1505 mm (59.3 in)
XT660X 1490 mm (58.7 in)
Ground clearance:
XT660R 210 mm (8.27 in)
XT660X 205 mm (8.07 in)
Minimum turning radius:
2400 mm (94.5 in)Weight:With oil and fuel:
XT660R 181.0 kg (399 lb)
XT660X 186.0 kg (410 lb)Engine:Engine type:
Liquid cooled 4-stroke, SOHC
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
660.0 cm³
Bore × stroke:
100.0 × 84.0 mm (3.94 × 3.31 in)Compression ratio:
10.00 :1
Starting system:
Electric starter
Lubrication system:
Dry sump
Engine oil:Type:
SAE10W30, SAE10W40, SAE15W40,
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) (2.20 Imp.qt)
With oil filter element replacement:
2.60 L (2.75 US qt) (2.29 Imp.qt)Cooling system:Coolant reservoir capacity (up to the
maximum level mark):
0.25 L (0.26 US qt) (0.22 Imp.qt)
Radiator capacity (including all routes):
1.00 L (1.06 US qt) (0.88 Imp.qt)
Air filter:Air filter element:
Oil-coated paper elementFuel:Recommended fuel:
Premium unleaded gasoline only
Fuel tank capacity:
15.0 L (3.96 US gal) (3.30 Imp.gal)
Fuel reserve amount:
5.0 L (1.32 US gal) (1.10 Imp.gal)Fuel injector:Manufacturer:
DENSO
Model/quantity:
297500-0390Spark plug (s):Manufacturer/model:
NGK/CR7E
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)Clutch:Clutch type:
Wet, multiple-discTransmission:Primary reduction system:
Spur gear
Primary reduction ratio:
75/36 (2.083)
Secondary reduction system:
Chain drive
Secondary reduction ratio:
45/15 (3.000)
Transmission type:
Constant mesh 5-speed
-20 -10 0
10 20 30
40
50 ˚C
SAE 10W-30
SAE 15W-40SAE 20W-40SAE 20W-50
SAE 10W-40
U5VKE1E0.book Page 1 Tuesday, July 18, 2006 1:00 PM
Page 86 of 92

SPECIFICATIONS
8-3
8
Recommended fluid:
DOT 4Rear brake:Type:
Single disc brake
Operation:
Right foot operation
Recommended fluid:
DOT 4Front suspension:Type:
Telescopic fork
Spring/shock absorber type:
Coil spring/oil damper
Wheel travel:
XT660R 225.0 mm (8.86 in)
XT660X 200.0 mm (7.87 in)Rear suspension:Type:
Swingarm (monocross)
Spring/shock absorber type:
Coil spring/gas-oil damper
Wheel travel:
XT660R 200.0 mm (7.87 in)
XT660X 191.0 mm (7.52 in)Electrical system:Ignition system:
Transistorized coil ignition (digital)
Charging system:
AC magnetoBattery:Model:
GT9B-4Voltage, capacity:
12 V, 8.0 Ah
Headlight:Bulb type:
Halogen bulbBulb voltage, wattage × quantity:Headlight:
12 V, 55 W/60.0 W × 1
Tail/brake light:
12 V, 5.0 W/21.0 W × 1
Front turn signal light:
12 V, 10.0 W × 2
Rear turn signal light:
12 V, 10.0 W × 2
Auxiliary light:
12 V, 5.0 W × 1
Meter lighting:
EL
Neutral indicator light:
LED
High beam indicator light:
LED
Turn signal indicator light:
LED
Fuel level warning light:
LED
Coolant temperature warning light:
LED
Engine trouble warning light:
LED
Immobilizer system indicator light:
LED
Fuses:Main fuse:
30.0 A
Headlight fuse:
20.0 A
Signaling system fuse:
10.0 A
Ignition fuse:
10.0 A
Parking lighting fuse:
10.0 A
Radiator fan fuse:
7.5 A
Fuel injection system fuse:
10.0 A
Backup fuse:
10.0 A
U5VKE1E0.book Page 3 Tuesday, July 18, 2006 1:00 PM