Page 69 of 90

PERIODIC MAINTENANCE AND MINOR REPAIR
6-31
6 4. If the fuse immediately blows
again, have a Yamaha dealer
check the electrical system.
EAUM1750
Replacing the headlight bulb This model is equipped with a quartz
bulb headlight. If the headlight bulb
burns out, replace it as follows.
1. Remove cowling A together with
the headlight unit. (See page 6-5.)
2. Disconnect the headlight coupler,
and then remove the headlight
bulb cover.
3. Remove the headlight bulb holder
by turning it counterclockwise, and
then remove the defective bulb.
WARNING
EWA10790
Headlight bulbs get very hot. There-
fore, keep flammable products away
from a lit headlight bulb, and do not
touch the bulb until it has cooleddown.
4. Place a new bulb into position, and
then secure it with the bulb holder.CAUTION:
ECA10660
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 adversely af-
1. Headlight bulb cover
2. Headlight coupler
1. Headlight bulb holder
2. Headlight bulb
Page 70 of 90
PERIODIC MAINTENANCE AND MINOR REPAIR
6-32
6fected. Thoroughly clean off any dirt
and fingerprints on the headlight
bulb using a cloth moistened with al-
cohol or thinner.
5. Install the bulb cover, and then
connect the coupler.
6. Install the cowling together with
the headlight unit.
7. Have a Yamaha dealer adjust the
headlight beam if necessary.
EAU24281
Replacing a turn signal light
bulb or the tail/brake light bulb 1. Remove the lens by removing the
screws.2. Remove the defective bulb by
pushing it in and turning it counter-
clockwise.
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
screws.
CAUTION:
ECA10680
Do not overtighten the screws, oth-erwise the lens may break.
1. Do not touch the glass part of the bulb.
1. Screw
1. Screw
Page 74 of 90

PERIODIC MAINTENANCE AND MINOR REPAIR
6-36
63. Lift the rear wheel off the ground
according to the procedure on
page 6-33.
4. Loosen the locknut on each side of
the swingarm.
5. Turn the drive chain slack adjust-
ing nuts fully in direction (a).
6. Remove the wheel axle by remov-
ing the axle nut.
7. Push the wheel forward, and then
remove the drive chain from the
rear sprocket.
NOTE:The drive chain cannot be disassem-bled.
8. Pull the wheel backward and move
the brake caliper away from the
wheel.
CAUTION:
ECA11070
Do not apply the brake after the
wheel has been removed together
with the brake disc, otherwise thebrake pads will be forced shut.
EAUM1781
To install the rear wheel
1. Install the drive chain onto the rear
sprocket.
2. Install the wheel, the washers and
the brake caliper bracket by insert-
ing the wheel axle from the left-
hand side.
NOTE:
Install the washer with the “N”
mark on the right-hand side and
the washer with the “O” mark on
the left-hand side. Be sure to install
both washers with their marks fac-
ing outward.
Make sure that the retainer on the
swingarm is inserted into the slot in
the brake caliper bracket.
Make sure that there is enough
space between the brake pads be-fore installing the wheel.
3. Lower the rear wheel so that it is
on the ground.
1. Brake caliper
2. Brake disc
1. Retainer
2. Slot
Page 76 of 90

PERIODIC MAINTENANCE AND MINOR REPAIR
6-38
6
EAU25921
Troubleshooting charts Starting problems or poor engine performance
WARNING
EWA10840
Keep away open flames and do not smoke while checking or working on the fuel system.
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the compression.
Supply fuel.
The engine does not start.
Check the compression.
Operate the electric starter.2. Compression
There is compression.
There is no compression.
Check the ignition.
Have a Yamaha dealer
check the vehicle.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the vehicle.
The engine does not start.
Have a Yamaha dealer
check the vehicle.
The engine does not start.
Check the battery.
Operate the electric starter.4. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the battery lead connections,
and charge the battery if necessary.
DryWet
Open the throttle halfway and operate
the electric starter.
Page 77 of 90

PERIODIC MAINTENANCE AND MINOR REPAIR
6-39
6 Engine overheating
WARNING
EWA10400
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, and then
slowly rotate the cap counterclockwise to the detent to allow any residual pressure to escape. When the hissingsound 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 coolantas soon as possible.
Wait until the
engine has cooled.
Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer checkand repair the cooling system.Add coolant. (See NOTE.)
Start the engine. If the engine overheats again,
have a
Yamaha dealer check
and repair the cooling system.
There is
leakage.
There is
no leakage.
Page 80 of 90

MOTORCYCLE CARE AND STORAGE
7-3
7
Never apply oil or wax to any
rubber and plastic parts, but
treat them with a suitable care
product.
Avoid using abrasive polishing
compounds as they will wearaway the paint.
NOTE:Consult a Yamaha dealer for advice onwhat products to use.
EAUM1900
Storage Short-term
Always store your motorcycle in a cool,
dry place and, if necessary, protect it
against dust with a porous cover.CAUTION:
ECA10810
Storing the motorcycle in a
poorly ventilated room or cover-
ing it with a tarp, while it is still
wet, will allow water and humid-
ity to seep in and cause rust.
To prevent corrosion, avoid
damp cellars, stables (because
of the presence of ammonia)
and areas where strong chemi-cals are stored.
Long-term
Before storing your motorcycle for sev-
eral months:
1. Follow all the instructions in the
“Care” section of this chapter.
2. Fill up the fuel tank and add fuel
stabilizer (if available) to prevent
the fuel tank from rusting and the
fuel from deteriorating.3. Perform the following steps to pro-
tect the cylinder, piston rings, etc.
from corrosion.
a. Remove the spark plug cap
and spark plug.
b. Pour a teaspoonful of engine oil
into the spark plug bore.
c. Install the spark plug cap onto
the spark plug, and then place
the spark plug on the cylinder
head so that the electrodes are
grounded. (This will limit spark-
ing during the next step.)
d. Turn the engine over several
times with the starter. (This will
coat the cylinder wall with oil.)
e. Remove the spark plug cap
from the spark plug, and then
install the spark plug and the
spark plug cap.
WARNING
EWA10950
To prevent damage or injury from
sparking, make sure to ground the
spark plug electrodes while turningthe engine over.
Page 81 of 90
MOTORCYCLE CARE AND STORAGE
7-4
7 4. Lubricate all control cables and the
pivoting points of all levers and
pedals as well as of the side-
stand/centerstand.
5. Check and, if necessary, correct
the tire air pressure, and then lift
the motorcycle so that both of its
wheels are off the ground. Alterna-
tively, turn the wheels a little every
month in order to prevent the tires
from becoming degraded in one
spot.
6. Cover the muffler outlets with plas-
tic bags to prevent moisture from
entering them.
7. Remove the battery and fully
charge it. Store it in a cool, dry
place and charge it once a month.
Do not store the battery in an ex-
cessively cold or warm place [less
than 0 °C (30 °F) or more than 30
°C (90 °F)]. For more information
on storing the battery, see page
6-28.
NOTE:Make any necessary repairs beforestoring the motorcycle.
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