2004 YAMAHA BANSHEE 350 engine

8-29
EBU00766
To change 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. Put the ATV on a level place.
2. Remove the radiator cover bolts, and then
remove the radiator cover.
3. Place a container under the engine and
remove the coolant drain bolts.
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1. Radiator cover 2. Radiator cover bolt (×3)
1. Cache de radiateur 2. Boulon du cache de
radiateur (×3)
1. Cubierta del radiador 2. Perno de la cubierta del
radiador (×3)
1. Drain bolt (×2)
1. Boulon de vidange (×2)
1. Perno de drenaje (×2)

8-35
cC
Hard water or salt water is harmful to the
engine. You may use soft water if you can’t
get distilled water.
11. Install the radiator cap.Recommended antifreeze:
High quality ethylene glycol antifreeze
containing corrosion inhibitors for
aluminum engines.
Antifreeze and water mixing ratio:
1:1
Total amount:
1.5 L
Coolant reservoir capacity:
0.28 L

8-37
12. Run the engine 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.
13. Fill the coolant reservoir with coolant up to
the maximum level.
14. Install the coolant reservoir cap and check
for coolant leakage.
NOTE:
If any leakage is found, ask a Yamaha dealer to
inspect the cooling system.
15. Install the radiator cover by installing the
bolts.

8-39
EBU00287
Spark plug inspection
The spark plugs are important engine compo-
nents and are easy to inspect. The condition of
the spark plugs can indicate the condition of the
engine.
Normally, all spark plugs from the same engine
should have the same color on the white porce-
lain insulator around the center electrode. The
ideal color at this point is a medium to light tan
color for a machine that is being ridden normal-
ly. If one spark plug shows a distinctly different
color, there could be something wrong with the
engine.
Do not attempt to diagnose such problems your-
self. Instead, take the machine to a Yamaha
dealer. You should periodically remove and
inspect the spark plugs because heat and
deposits will cause any 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.

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1. Air filter element 2. Element guide
1. Elément du filtre à air 2. Guide de l’élément
1. Elemento filtrante de aire 2. Guía del elemento
8-45
3. Remove the air filter element, and sepa-
rate it from the guide.
4. Wash the element gently but thoroughly 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.
5. Squeeze the excess solvent out of the filter
and let it dry.
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Do not twist the filter element when
squeezing it.

8-49
NOTE:
The air filter element should be cleaned every
20–40 hours. It should be cleaned and lubricat-
ed more often if the machine is operated in
extremely dusty areas. Each time filter element
maintenance is performed, check the air inlet to
the filter case for obstructions. Check the air
cleaner rubber joint to the carburetor and mani-
fold fittings for an air-tight seal. Tighten all fit-
tings securely to avoid the possibility of unfil-
tered 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, causing rapid engine wear and
possible engine damage. Additionally, opera-
tion without the filter element will affect car-
buretor jetting with subsequent poor perfor-
mance and possible engine overheating.

8-51
EBU00300
Carburetor settings
In extremely cold weather, it is necessary to
change the carburetor settings to maintain opti-
mum engine performance and to prevent engine
damage.
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8Improperly servicing or adjusting the carbu-
retors could cause malfunction with the pos-
sibility of an accident or the carburetors
could leak fuel, which would be a fire hazard.
8Carburetor adjustments should only be per-
formed by a Yamaha dealer. Do not attempt
to perform these procedures unless you
have mechanical knowledge and the neces-
sary tools.
8Do not perform this procedure while the
engine is hot. Place a rag under each carbu-
retor to catch any fuel. Wipe up any spilled
fuel completely.
8After servicing the carburetors, always check
throttle operation before operating the ATV
to make sure it is working correctly.

8-67
EBU03021
Idle speed adjustment
NOTE:
A diagnostic tachometer must be used for this
procedure.
NOTE:
The throttle cables and carburetor synchroniza-
tion must be set properly before adjusting the
idle speed.
1. Adjust the pilot air screws.
8Turn in both pilot air screws until they
lightly seat.
8Turn out both pilot air screws to specifi-
cation. (Refer to the “Carburetor settings”
section.)
2. Remove the seat.
3. Start the engine and warm it up for a few
minutes at approximately 1,000 to 2,000
r/min.
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1. Pilot air screw
1. Vis d’air de ralenti
1. Tornillo de aire piloto