2004 YAMAHA WOLVERINE 350 engine

8-1
EBU00516
PERIODIC MAINTENANCE AND
ADJUSTMENTPeriodic inspection, adjustment and lubrication will
keep your machine in the safest and most efficient
condition possible. Safety is an obligation of the
machine owner. The most important points of ma-
chine inspection, adjustment and lubrication are
explained on the following pages.
WARNING
Never service an engine while it is running.
Moving parts can catch clothing or parts of the
body, causing injury. Electrical components
can cause shocks or can start fires. Turn off
the engine when performing maintenance un-
less otherwise specified. Have a Yamaha deal-
er perform service if you are not familiar with
machine service.
U5WH60.book Page 1 Friday, October 31, 2003 2:45 PM

8-7
EBU00262
PERIODIC MAINTENANCE/LUBRICATION
ITEM ROUTINEINITIAL EVERY
1
month3
months6
months6
months1
year
Valves*Check valve clearance.
Adjust if necessary.
Spark plugCheck condition.
Adjust gap and clean.
Replace if necessary.Air filter elementClean.
Replace if necessary.Every 20–40 hours
(More often in wet or dusty areas.)
Carburetor*Check and adjust idle speed/starter operation.
Adjust if necessary.Crankcase breather
system*Check breather hose for cracks or damage.
Replace if necessary.Exhaust system*Check for leakage.
Tighten if necessary.
Replace gasket(s) if necessary.Fuel line*Check fuel hose for cracks or damage.
Replace if necessary.Engine oil
Replace. (Warm engine before draining.)Engine oil filter cartridge
Replace.Engine oil strainer*
Clean.Final gear oilCheck oil level/oil leakage.
Replace every 12 months.Front brake*Check operation/fluid leakage. (See NOTE page 8-8.)
Correct if necessary.Rear brakeCheck operation.
Adjust if necessary.V-belt*Check operation.
Check for cracks or damage.U5WH60.book Page 7 Friday, October 31, 2003 2:45 PM

8-19 1. Engine oil filler cap
1. Bouchon de remplissage d’huile de moteur
1. Tapa de relleno de aceite de motor
1. Maximum level mark 2. Minimum level mark
1. Repère de niveau maximum 2. Repère de niveau minimum
1. Marca de nivel máximo 2. Marca de nivel mínimo
EBU14540
Engine oil and oil filter cartridge
The engine oil level should be checked before
each ride. In addition, the oil must be changed and
the oil filter cartridge replaced at the intervals
specified in the periodic maintenance and lubrica-
tion chart.
To check the engine oil level
1. Place the ATV on a level surface.
2. Start the engine, warm it up for several min-
utes, and then turn it off.
3. Wait a few minutes until the oil settles.
4. Remove the engine oil filler cap and wipe off
the dipstick with a clean rag.
5. Insert the dipstick in the oil filler hole (without
screwing it in), and then remove it again to
check the oil level.NOTE:_ The engine oil should be between the minimum
and maximum level marks. _
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8-21 1. Engine oil drain bolt
1. Boulon de vidange de l’huile
1. Perno de drenaje del aceite de motor
6. If the engine oil is at or below the minimum
level mark, add sufficient oil of the recom-
mended type to raise it to the correct level.
7. Insert the dipstick into the oil filler hole, and
then tighten the oil filler cap.
To change the engine oil (with or without oil fil-
ter cartridge replacement)
1. Start the engine, warm it up for several min-
utes, and then turn it off.
2. Place an oil pan under the engine to collect
the used oil, and then remove the engine oil
filler cap.
3. Remove the engine oil drain bolt to drain the
oil from the crankcase.
U5WH60.book Page 21 Friday, October 31, 2003 2:45 PM

8-25 1. O-ring
1. Joint torique
1. Junta tórica
1. Torque wrench
1. Clé dynamométrique
1. Llave de apriete
5. Apply a light coat of engine oil to the O-ring of
the new oil filter cartridge.NOTE:_ Make sure the O-ring is seated properly. _6. Install the new oil filter cartridge with an oil fil-
ter wrench, and then tighten it to the specified
torque with a torque wrench.
7. Install the engine oil drain bolt, and then tight-
en it to the specified torque. Tightening torque:
Oil filter cartridge:
17 Nm (1.7 m·kgf)
Tightening torque:
Engine oil drain bolt:
23 Nm (2.3 m·kgf)
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8-27
8. Add the specified amount of recommended
engine oil, and then install the engine oil filler
cap and tighten it.CAUTION:_

In order to prevent clutch slippage (since
the engine oil also lubricates the clutch),
do not mix any chemical additives. Do not
use oils with a diesel specification of “CD”
or oils of a higher quality than specified. In
addition, do not use oils labeled “ENERGY
CONSERVING II” or higher.


Make sure that no foreign material enters
the crankcase.
_
Recommended engine oil:
See page 10-2.
Oil quantity:
Without oil filter cartridge replacement:
2.2 L
With oil filter cartridge replacement:
2.3 L
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8-29
‘1. Final gear oil
2. Final gear oil filler bolt
3. Proper oil level
1. Huile de transmission finale
2. Boulon de remplissage d’huile du carter de transmission finale
3. Niveau correct
1. Aceite de la transmisión final
2. Perno del orificio de llenado de aceite de la transmisión final
3. Nivel de aceite adecuado
9. Start the engine and warm it up for several
minutes. While warming up, check for oil
leakage. If oil leakage is found, turn the en-
gine off immediately and check for the cause.
10. Turn the engine off, and then check the oil
level and correct it if necessary.
EBU11452
Final gear oil
Final gear oil measurement
1. Place the machine on a level surface.
2. Remove the oil filler bolt, and then check the
oil level in the final gear case.NOTE:_ The oil level should be at the brim of the filler hole. _3. If the oil is below the brim of the filler hole,
add sufficient oil of the recommended type to
raise it to the correct level.CAUTION:_ Be sure no foreign material enters the final
gear case. _4. Install the oil filler bolt.
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8-37
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.
Specified spark plug:
DR8EA (NGK)
U5WH60.book Page 37 Friday, October 31, 2003 2:45 PM