2004 YAMAHA WOLVERINE 450 engine

8-61
CAUTION:_ Hard water or salt water is harmful to the en-
gine. You may use soft water if you cannot get
distilled water. _14. 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.
15. Check for coolant leakage.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):
0.25 L
U5ND61.book Page 61 Thursday, June 5, 2003 7:02 PM

8-67
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 a
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.
Specified spark plug:
DR8EA (NGK)
U5ND61.book Page 67 Thursday, June 5, 2003 7:02 PM

8-73 1. Air filter element assembly
1.Élément de filtre à air
1. Conjunto del elemento del filtro de aire
1. Air filter element frame 2. Air filter element
1. Armature d’élément de filtre à air
2.Élément de filtre à air
1. Bastidor del elemento del filtro de aire
2. Elemento del filtro de aire
3. Remove the air filter element assembly, and
then remove the air filter element from its
frame.
4. Wash the element gently but thoroughly 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. _
U5ND61.book Page 73 Thursday, June 5, 2003 7:02 PM

8-75
5. Squeeze the excess solvent out of the air fil-
ter element and let it dry.CAUTION:_ Do not twist the air filter element when squeez-
ing it. _6. Inspect the air filter element and replace it if
damaged.
7. Apply foam air filter oil to the air filter element.
If foam air filter oil is not available, engine oil
may be used.NOTE:_ The air filter element should be wet but not drip-
ping. _8. Pull the air filter element over its frame.
9. Install the air filter element assembly.
10. Install the air filter case cover by hooking the
holders.
11. Install the seat.
U5ND61.book Page 75 Thursday, June 5, 2003 7:02 PM

8-77
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 the air filter element mainte-
nance is performed, check the air inlet to the filter
case for obstructions. Check the air filter case rub-
ber 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. _
U5ND61.book Page 77 Thursday, June 5, 2003 7:02 PM

8-79 1. V-belt cooling duct check hose
1. Flexible de contrôle du conduit de refroidissement de la courroie
trapézoïdale
1. Manguera de comprobación del conducto de enfriamiento de
la correa trapezoidal
1. V-belt case drain plug
1. Boulon de vidange du carter de courroie trapézoïdale
1. Tapón de drenaje de la caja de la correa trapezoidal
EBU06411
V-belt cooling duct check hose
If dust or water collects in the V-belt cooling duct
check hose, remove the hose and clean it.
EBU08741
V-belt case drain plug
After riding in water deep enough to allow it to en-
ter the V-belt case, remove this plug to drain the
water from the case.NOTE:_ If water drains from the V-belt case after removing
the plug, have a Yamaha dealer inspect the ATV
as the water may affect other engine parts. _
U5ND61.book Page 79 Thursday, June 5, 2003 7:02 PM

8-81
EBU00296
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.
U5ND61.book Page 81 Thursday, June 5, 2003 7:02 PM

8-83 1. Throttle stop screw
1. Vis d’arrêt de l’accélérateur
1. Tornillo de tope del acelerador
EBU12580
Idle speed adjustmentNOTE:_ A diagnostic tachometer must be used for this pro-
cedure. _1. Start the engine and warm it up for a few min-
utes at approximately 1,000 to 2,000 r/min.
Occasionally rev the engine to 4,000 to
5,000 r/min. The engine is warm when it
quickly responds to the throttle.
2. Remove panel D. (See pages 8-17–8-19 for
removal and installation procedures.)
3. Connect the tachometer to the spark plug
lead, and then set the idle to the specified
idling speed by adjusting the throttle stop
screw. Turn the screw in direction
a to in-
crease the engine speed, and in direction
b
to decrease the engine speed.
4. Install the panel. Specified idle speed:
1,450–1,550 r/min
U5ND61.book Page 83 Thursday, June 5, 2003 7:02 PM