2003 YAMAHA YFM660R engine overheat

4-5 1. Reverse indicator light “R”
2. Neutral indicator light “N”
3. Coolant temperature warning light “”
1. Témoin de marche arrière “R”
2. Témoin de point mort “N”
3. Témoin d’avertissement de la température du liquide de
refroidissement “”
1. Luz de control de marcha atrás “R”
2. Luz de control de punto muerto “N”
3. Luz de aviso de la temperatura del refrigerante “”
EBU00713
Coolant temperature warning light “”
When the coolant temperature reaches a specified
level, this light comes on to warn that the coolant
temperature is too hot. If the light comes on during
operation, stop the engine as soon as it is safe to
do so and allow the engine to cool down for about
10 minutes.
The coolant temperature warning light circuit can
be checked according to the procedure on page
4-7.CAUTION:

The engine may overheat if the ATV is
overloaded. If this happens, reduce the
load to specification.


Restart after making sure that the light is
out. Continuous use while the light is on
may cause damage to the engine.
U5LP62.book Page 5 Wednesday, May 8, 2002 11:24 AM

4-25
WARNING


Always set the parking brake before start-
ing the engine. The ATV could start mov-
ing unexpectedly if the parking brake is not
applied. This could cause loss of control or
a collision.


Always be sure you have released the
parking brake before you begin to ride. The
brake could overheat if you ride the ATV
without releasing the parking brake. You
could lose braking performance which
could cause an accident. You could also
wear out the brakes prematurely.
U5LP62.book Page 25 Wednesday, May 8, 2002 11:24 AM

8-33 1. Coolant reservoir cap
2. Maximum level mark
3. Minimum level mark
1. Bouchon du vase d’expansion
2. Repère de niveau maximum
3. Repère de niveau minimum
1. Tapa del depósito de líquido refrigerante
2. Marca de nivel máximo
3. Marca de nivel mínimo
EBU01015
Cooling system
1. Check the coolant level in the coolant reser-
voir when the engine is cold as the coolant
level will vary with engine temperature. The
coolant level should be between the maxi-
mum and minimum marks.
2. If the level is low, remove the coolant reser-
voir cap, and then add coolant or distilled wa-
ter to raise it to the specified level.CAUTION:_ Hard water or salt water is harmful to the en-
gine. You may use soft water if you can’t get
distilled water. _NOTE:_

If water is added, have a Yamaha dealer
check the antifreeze content of the coolant as
soon as possible.


The radiator fan operation is completely auto-
matic. It is switched on or off according to the
coolant temperature in the radiator.
_If your ATV overheats, see page 8-124 for details.Coolant reservoir capacity:
0.29 L
U5LP62.book Page 33 Wednesday, May 8, 2002 11:24 AM

8-51 1. Hose
1. Flexible
1. Manguera
11. Install the air filter case cover and be sure to
connect the hose.
12. Install the seat.NOTE:_ The air filter element should be cleaned every 20–
40 hours. It should be cleaned and lubricated more
often if the machine is operated in extremely dusty
areas. Each time air filter element maintenance is
performed, check the air inlet to the air filter case
for obstructions. Check the air filter element rubber
joint to the carburetor and manifold fittings for an
airtight seal. Tighten all fittings securely to avoid
the possibility of unfiltered air entering the engine. _CAUTION:_ Never operate the engine with the air filter ele-
ment removed. This will allow unfiltered air to
enter, causing rapid engine wear and possible
engine damage. Additionally, operation with-
out the air filter element will affect carburetor
jetting with subsequent poor performance and
possible engine overheating. _
U5LP62.book Page 51 Wednesday, May 8, 2002 11:24 AM

8-124
Engine overheatingNOTE:If it is difficult to get the recommended coolant, tap water can be temporarily used, provided that it is
changed to the recommended coolant as soon as possible.
WARNING
Wait for the engine and radiator to cool before removing the radiator cap. You could be burned by
hot fluid and steam blown out under pressure. Always put a thick rag over the cap when opening.
Allow any remaining pressure to escape before completely removing the cap. Wait until the
engine has cooled.
Check the coolant level in the
reservoir tank and/or radiator.
Level is OK.Level is low, check the
cooling system for leakage.
No
leakage.Leakage.
Ask a Yamaha dealer to inspect
and repair the cooling system.Add coolant. (See NOTE.)
Restart the engine. If the engine overheats again, ask a
Yamaha dealer to inspect and/or repair the cooling system.
U5LP62.book Page 124 Wednesday, May 8, 2002 11:24 AM