engine YAMAHA YFZ450 2006 Workshop Manual

8-41
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Be sure to apply LOCTITEto the engine
guard bolts before installing them.
Tightening torque:
Engine guard bolt:
7 Nm (0.7 m0kgf)
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8-43
EBU10151
Cooling system
1. Check the coolant level in the coolant
reservoir when the engine is cold as the
coolant level will vary with engine tempera-
ture.
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.
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Hard water or salt water is harmful to the
engine. You may use soft water if you can’t
get distilled water.
Coolant reservoir capacity
(up to the maximum level mark):
0.25 L
1. Maximum level mark 2. Minimum level mark
3. Coolant reservoir 4. Coolant reservoir cap
1. Repère maximum 2. Repère minimum
3. Vase d’expansion
4. Bouchon du vase d’expansion
1. Marca de máximo 2. Marca de mínimo
3. Depósito de refrigerante
4. Tapa del depósito de refrigerante
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8-47
EBU14130
Changing the coolant
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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 8-19 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.
1. Coolant drain bolt (×2) 2. Trough1. Boulon de vidange du liquide de refroidissement (×2)
2. Feuille de papier pliée comme illustré
1. Perno de drenaje de refrigerante (×2)
2. Elemento de paso
1. Radiator cap
1. Bouchon de radiateur1. Tapa del radiador
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8-51
Recommended antifreeze:
High quality ethylene glycol antifreeze
containing corrosion inhibitors for
aluminum engines.
Antifreeze and water mixing ratio:
1:1
Total amount:
1.30 L
Coolant reservoir capacity
(up to the maximum level mark):
0.29 L
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8-53
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Hard water or salt water is harmful to the
engine. You may use soft water if you cannot
get distilled water.
12. Install the radiator cap and the coolant
reservoir cap.
13. Start the engine and let it idle for several
minutes. 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 radiator.
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.
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8-55
EBU14142
Spark plug inspection
Removal
1. Remove the seat. (See page 4-27 for seat
removal and installation procedures.)
2. Remove the bolts and the quick fastener
screws.
3. Remove the fuel tank cap by turning it
counterclockwise.
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8Always turn off the engine when removing
the fuel tank cap.
8Do not remove the fuel tank cap immedi-
ately after the engine has been running
and is still very hot.
8Do not spill gasoline on the engine,
exhaust pipe or muffler.
8Never 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.
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
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8-59
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 compo-
nent 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 electrode erosion becomes excessive, or if
carbon and other deposits are excessive, you
should replace the spark plug with the specified
plug.
1. Spark plug wrench1. Clé à bougie1. Llave de bujía
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8-69
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.
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Always use parts cleaning solvent to clean
the air filter element. Never use low flash
point solvents or gasoline to clean the air fil-
ter element because the engine could catch
fire or explode.
1. Wing bolt 2. Air filter element1. Boulon papillon 2.Élément du filtre à air1. Perno de aletas 2Elemento del filtro de aire
1. Air filter element 2. Frame
1. Élément du filtre à air 2.Armature1. Elemento del filtro de aire 2Bastidor
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8-73
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 ele-
ment 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 manifold fittings for an
airtight seal. Tighten all fittings securely to avoid
the possibility of unfiltered air entering the
engine.
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Never operate the engine with the air filter
element removed. This will allow unfiltered
air to enter the engine, causing rapid engine
wear and possible engine damage.
Additionally, operation without the air filter
element will affect carburetor jetting with
subsequent poor performance and possible
engine overheating.
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EBU02960
Carburetor adjustment
The carburetor is a vital part of the engine and
requires very sophisticated adjustment. Most
adjusting should be left to a Yamaha dealer who
has the professional knowledge and experience
to do so. However, the idling speed may be per-
formed by the owner as a part of the usual main-
tenance routine.
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The carburetor was set at the Yamaha facto-
ry after many tests. If the settings are dis-
turbed by someone without sufficient techni-
cal knowledge, poor engine performance and
damage may result.
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