2008 YAMAHA XT660Z engine overheat

INSTRUMENT AND CONTROL FUNCTIONS
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EAUB1520
Neutral indicator light “ N”
This indicator light comes on when the
transmission is in the neutral position.
The electrical circuit of the neutral indi-
cator light can be checked by turning
the key to "ON".
If the indicator light does not come on
for a few seconds, then go off, have a
Yamaha dealer check the electrical cir-
cuit.
EAUB1530
High beam indicator light “ 1”
This indicator light comes on when the
high beam of the headlight is switched
on. The electrical circuit of the high
beam indicator light can be checked
by turning the key to "ON".
If the indicator light does not come on
for a few seconds, then go off, have a
Yamaha dealer check the electrical cir-
cuit.
EAU11440
Coolant temperature warning
light “u ”
This warning light comes on when the
engine overheats. When this occurs,
stop the engine immediately and allow
the engine to cool. The electrical circuit of the warning
light can be checked by turning the
key to “ON”.
If the warning light does not come on
for a few seconds, then go off, have a
Yamaha dealer check the electrical cir-
cuit.
ECA10020
CAUTION:
Do not operate the engine if it is
overheated.
EAU11530
Engine trouble warning light “ U”
This warning light comes on or flashes
when an electrical circuit monitoring
the engine is defective. When this oc-
curs, have a Yamaha dealer check the
self-diagnosis system. (See page 3-7
for an explanation of the self-diagnosis
device.)
The electrical circuit of the warning
light can be checked by turning the
key to “ON”. If the warning light does
not come on for a few seconds, then
go off, have a Yamaha dealer check
the electrical circuit.
EAU26873
Immobilizer system indicator
light “ ”
The electrical circuit of the indicator
light can be checked by turning the
key to “ON”.
If the inidcator light does not come on
for a few seconds, then go off, have a
Yamaha dealer check the electrical cir-
cuit.
When the key is turned to “OFF” and
30 seconds have passed, the indicator
light will start flashing indicating the
immobilizer system is enabled. After
24 hours have passed, the indicator
light will stop flashing, however the im-
mobilizer system is still enabled.
This model is also equipped with a
self-diagnosis device for the immobi-
lizer system. (See page 3-7 for an ex-
planation of the self-diagnosis device.)

XT660Z 01-03 ING 10-03-2008 16:11 Pagina 3-4

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OPERATION AND IMPORTANT RIDING POINTS
EAU16810
Tips for reducing fuel
consumption
Fuel consumption depends largely on
your riding style. Consider the follow-
ing tips to reduce fuel consumption:
●Shift up swiftly, and avoid high en-
gine speeds during acceleration.
●Do not rev the engine while shift-
ing down, and avoid high engine
speeds with no load on the en-
gine.
●Turn the engine off instead of let-
ting it idle for an extended length
of time (e.g., in traffic jams, at traf-
fic lights or at railroad crossings).
EAU16841
Engine break-in
There is never a more important peri-
od in the life of your engine than the
period between 0 and 1600 km (1000
mi). For this reason, you should read
the following material carefully.
Since the engine is brand new, do not
put an excessive load on it for the first
1600 km (1000 mi). The various parts
in the engine wear and polish them-
selves to the correct operating clear-
ances. During this period, prolonged
full-throttle operation or any condition
that might result in engine overheating
must be avoided.
EAU17100
0-1000 km (0-600 mi)
Avoid prolonged operation above
4500 r/min.
1000-1600 km (600-1000 mi)
Avoid prolonged operation above
6000 r/min.
ECA10301CAUTION:
After 1000 km (600 mi) of operation,
the engine oil must be changed and
the oil filter cartridge or element re-
placed.
1600 km (1000 mi) and beyond
The vehicle can now be operated nor-
mally.
5-3

XT660Z 04-06 ING 11-03-2008 8:30 Pagina 5-3

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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.

XT660Z 04-06 ING 11-03-2008 8:31 Pagina 6-13

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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

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INDEX
Tire information .............................6-18
Tire inspection ..............................6-18
Tool kit ................................................6-1
Tripmeter and tachometer modes ......3-6
Troubleshooting ................................6-39 Troubleshooting charts .................6-40
Engine overheating .......................6-41
Turn signal indicator light ...................3-3
Turn signal light bulb, replacing........6-34
Turn signal switch...............................3-9
V Valve clearance ................................6-16
Vehicle identification number .............9-1
W Warning lights ....................................3-3
Wheel bearings, checking ................6-29
Wheels, spoke..................................6-19

XT660Z 07-10 ING 11-03-2008 8:33 Pagina 3