Page 50 of 90

PERIODIC MAINTENANCE AND MINOR REPAIR
6-12
6
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.
EAUM1721
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.
CAUTION:
ECA10470
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 engine may not be
sufficiently cooled and the cool-
ing 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.WARNING
EWA10380
Never attempt to remove the radiatorcap when the engine is hot.
5. Install the cowling.
1. Coolant reservoir
2. Maximum level mark
3. Minimum level markCoolant reservoir capacity (up to the
maximum level mark):
0.25 L (0.26 US qt) (0.22 Imp.qt)
Page 52 of 90

PERIODIC MAINTENANCE AND MINOR REPAIR
6-14
611. 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 rec-
ommended coolant into the radia-
tor and reservoir.
CAUTION:
ECA10470
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 engine may not be
sufficiently cooled and the cool-
ing 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.16. Check the coolant level in the res-
ervoir. If necessary, remove the
coolant reservoir cap, add coolant
to the maximum level mark, and
then install the cap.
17. Start the engine, and then check
the vehicle for coolant leakage. If
coolant is leaking, have a Yamaha
dealer check the cooling system.
18. Install the cowling, the panel and
the seat.
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)
Page 82 of 90

SPECIFICATIONS
8-1
8
Dimensions:Overall length:
XT660R 2240 mm (88.2 in)
XT660X 2150 mm (84.6 in)
Overall width:
XT660R 845 mm (33.3 in)
XT660X 865 mm (34.1 in)
Overall height:
XT660R 1230 mm (48.4 in)
XT660X 1210 mm (47.6 in)
Seat height:
XT660R 865 mm (34.1 in)
XT660X 870 mm (34.3 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 (40.27 cu.in)
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 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) (2.20 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)Electronic fuel injection:Manufacturer:
DENSO
Model:
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
Page 84 of 90

SPECIFICATIONS
8-3
8
Front 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:
A.C. magnetoBattery:Model:
GT9B-4
Voltage, capacity:
12 V, 8.0 AhHeadlight:Bulb type:
Halogen bulbBulb voltage, wattage x quantity:Headlight:
12 V, 55 W/60.0 W × 1
Tail/brake light:
12 V, 5.0/21.0 W × 1Front 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 indicator 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 ARadiator fan fuse:
7.5 A
Electronic fuel injection fuse:
10.0 A
Backup fuse:
10.0 A