engine YAMAHA YFZ450 2005 Notices Demploi (in French)

8-39
CAUTION:_ Be sure to apply LOCTITE
® to the engine guard
bolts before installing them.
_
Tightening torque:
Engine guard bolt:
7 Nm (0.7 m·kgf)
U5TG61.book Page 39 Friday, April 2, 2004 11:28 AM

8-41 1. Maximum level mark 2. Minimum level mark
3. Coolant reservoir 4. Coolant reservoir cap
1. Repère de niveau maximum 2. Repère de niveau minimum
3. Vase d’expansion 4. Bouchon du vase d’expansion
1. Marca de nivel máximo 2. Marca de nivel mínimo
3. Depósito de refrigerante
4. Tapa del depósito de líquido refrigerante
EBU10151
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.NOTE:_ The coolant should be between the minimum and
maximum level marks. _2. If the coolant is at or below the minimum level
mark, remove the coolant reservoir cap, and
then add coolant or distilled water 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. _
Coolant reservoir capacity
(up to the maximum level mark):
0.29 L
U5TG61.book Page 41 Friday, April 2, 2004 11:28 AM

8-45 1. Coolant drain bolt 2. Trough
1. Boulon de vidange du liquide de refroidissement
2. Feuille de papier pliée comme illustré
1. Perno de drenaje de refrigerante
2. Elemento de paso
1. Radiator cap
1. Bouchon de radiateur
1. Tapa del radiador
EBU14130
Changing the coolant
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. _1. Place the ATV on a level surface.
2. Remove panel A. (See page 8-17 for panel
removal and installation procedures.)
3. Place a container under the engine, and then
remove the coolant drain bolt. (Use a trough
or a similar object as shown.)
4. Remove the radiator cap.
U5TG61.book Page 45 Friday, April 2, 2004 11:28 AM

8-51
CAUTION:_ Hard water or salt water is harmful to the en-
gine. You may use soft water if you cannot get
distilled water. _12. Install the radiator cap and the coolant reser-
voir cap.
13. Start the engine and let it idle for several min-
utes. Stop the engine, and then check the
coolant level in the radiator. If it is low, add
more coolant until it reaches the top of the ra-
diator.
14. Check the coolant level in the reservoir. If it is
low, add coolant to the maximum level mark.
15. Start the engine and then check for coolant
leakage.NOTE:_ If any leakage is found, have a Yamaha dealer
check the cooling system. _16. Install the panel.
U5TG61.book Page 51 Friday, April 2, 2004 11:28 AM

8-53 1. Panel 2. Bolt (× 2)
3. Quick fastener screw (× 2) 4. Fuel tank cap
1. Cache 2. Boulon (× 2)
3. Vis à serrage rapide (× 2)
4. Bouchon du réservoir de carburant
1. Panel 2. Perno (× 2)
3. Perno del fijador rápido (× 2)
4. Tapón del depósito de combustible
EBU14142
Spark plug inspection
Removal
1. Remove the seat. (See page 4-27 for seat re-
moval and installation procedures.)
2. Remove the bolts and the quick fastener
screws.
3. Remove the fuel tank cap by turning it coun-
terclockwise.
WARNING
_

Always turn off the engine when removing
the fuel tank cap.


Do not remove the fuel tank cap immedi-
ately after the engine has been running
and is still very hot.


Do not spill gasoline on the engine, ex-
haust pipe or muffler.


Never remove the fuel tank cap while
smoking, or in the vicinity of sparks, open
flames, or other sources of ignition such
as the pilot lights of water heaters and
clothes dryers.
_
U5TG61.book Page 53 Friday, April 2, 2004 11:28 AM

8-57 1. Spark plug wrench
1. Clé à bougie
1. Llave de bujía
8. Use the spark plug wrench in the owner’s tool
kit to remove the spark plug as shown.
Inspection
The spark plug is an important engine component
and is easy to inspect. The condition of the spark
plug can indicate the condition of the engine.
The ideal color on the white insulator around the
center electrode is a medium-to-light tan color for
an ATV that is being ridden normally.
Do not attempt to diagnose such problems your-
self.
Instead, take the ATV to a Yamaha dealer. You
should periodically remove and inspect the spark
plug because heat and deposits will cause the
spark plug to slowly break down and erode. If elec-
trode erosion becomes excessive, or if carbon and
other deposits are excessive, you should replace
the spark plug with the specified plug.
U5TG61.book Page 57 Friday, April 2, 2004 11:28 AM

8-67 1. Wing bolt 2. Air filter element
1. Boulon papillon 2.Élément du filtre à air
1. Perno de aletas 2. Elemento del filtro de aire
1. Air filter element 2. Frame
1.Élément du filtre à air 2. Armature
1. Elemento del filtro de aire 2. Bastidor
3. Remove the air filter element by removing the
wing bolt.
4. Remove the air filter element from its frame.
5. Wash the air filter element gently but thor-
oughly in solvent.
WARNING
_ Always use parts cleaning solvent to clean the
air filter element. Never use low flash point sol-
vents or gasoline to clean the air filter element
because the engine could catch fire or ex-
plode. _
U5TG61.book Page 67 Friday, April 2, 2004 11:28 AM

8-71
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 intake duct between
the air filter case and the carburetor and the mani-
fold fittings for an airtight seal. Tighten all fittings
securely to avoid the possibility of unfiltered air en-
tering the engine. _CAUTION:_ Never operate the engine with the air filter ele-
ment removed. This will allow unfiltered air to
enter the engine, causing rapid engine wear
and possible engine damage. Additionally, op-
eration without the air filter element will affect
carburetor jetting with subsequent poor per-
formance and possible engine overheating. _
U5TG61.book Page 71 Friday, April 2, 2004 11:28 AM

8-73
EBU02960
Carburetor adjustment
The carburetor is a vital part of the engine and re-
quires very sophisticated adjustment. Most adjust-
ing should be left to a Yamaha dealer who has the
professional knowledge and experience to do so.
However, the idling speed may be performed by
the owner as a part of the usual maintenance rou-
tine.CAUTION:_ The carburetor was set at the Yamaha factory
after many tests. If the settings are disturbed
by someone without sufficient technical
knowledge, poor engine performance and
damage may result. _
U5TG61.book Page 73 Friday, April 2, 2004 11:28 AM

8-75
EBU13970
Idle speed adjustment
A special tester is needed to check the engine
r/min on this model.
Therefore, take the ATV to a Yamaha dealer to
have the idle speed adjusted.
EBU03030
Valve clearance adjustment
The correct valve clearance changes with use, re-
sulting in improper fuel/air supply or engine noise.
To prevent this, the valve clearance must be ad-
justed regularly. This adjustment however, should
be left to a professional Yamaha service techni-
cian. Specified idle speed:
1,750–1,850 r/min
U5TG61.book Page 75 Friday, April 2, 2004 11:28 AM