2004 YAMAHA BIG BEAR PRO 400 engine

8-17 1. Engine oil filter element cover bolt (× 3)
2. Oil filter element cover
1. Boulon de couvercle de l’élément de filtre à huile moteur (× 3)
2. Couvercle de l’élément de filtre à huile
1. Perno de la tapa del elemento del filtro de aceite de motor (× 3)
2. Tapa del elemento del filtro de aceite
1. Engine oil filter element 2. O-ring (× 2)
1.Élément du filtre à huile moteur 2. Joint torique (× 2)
1. Element del filtro de aceite de motor 2. Junta tórica (× 2)
6. Remove the shift pedal by removing the bolt.
7. Remove the oil filter element cover, and then
the oil filter element.
8. Clean the oil strainer and oil filter element
with solvent.
9. Inspect the O-ring and replace it if damaged.
10. Install the oil filter element, O-ring, oil filter el-
ement cover, compression spring, oil strainer
and drain bolt. Tighten the drain bolt to the
specified torque.CAUTION:_ Before installing the drain bolt, be sure to in-
stall the O-ring, compression spring and oil
strainer. _
Tightening torque
Drain bolt (engine):
32 Nm (3.2 m·kgf)
Oil filter element cover bolt:
10 Nm (1.0 m·kgf)
U4SH6B.book Page 17 Tuesday, May 27, 2003 4:39 PM

8-19
11. Fill the engine with oil and install the oil filler
cap.CAUTION:_ Make sure that no foreign material enters the
crankcase. _
Recommended oil:
See page 10-2.
Oil quantity:
Without oil filter element replacement:
2.40 L
With oil filter element replacement:
2.50 L
U4SH6B.book Page 19 Tuesday, May 27, 2003 4:39 PM

8-21
12. Install the clamp by installing the screw.
13. Install the shift pedal by installing the bolt.
14. Warm up the engine for several minutes at
idle speed. Check for oil leakage while warm-
ing up.CAUTION:_ If oil leakage is found, stop the engine immedi-
ately and check for the cause. _
U4SH6B.book Page 21 Tuesday, May 27, 2003 4:39 PM

8-23 1. Bolt (× 3)
1. Boulon (× 3)
1. Perno (× 3)
1. Oil filler bolt
1. Boulon de l’orifice de remplissage d’huile
1. Perno del orificio de llenado de aceite
EBU00462
Transfer gear oil replacementNOTE:When replacing the transfer gear oil, replace the
engine oil also.1. Remove the transfer gear case guard.
2. Place the machine on a level place.
3. Place a container under the transfer gear
case.
4. Remove the oil filler bolt and drain bolt to
drain the oil.
5. Install the drain bolt and tighten to specifica-
tion.
Tightening torque:
Drain bolt (transfer gear case):
20 Nm (2.0 m·kgf)
E-8.fm Page 23 Thursday, May 29, 2003 11:49 AM

8-25 1. Drain bolt
1. Boulon de vidange
1. Perno de drenaje
6. Fill the transfer gear case with oil.CAUTION:
Be sure no foreign material enters the transfer
gear case.7. Install the filler bolt and tighten to specifica-
tion.
8. Check for oil leakage. If oil leakage is found,
check for the cause.
9. Reinstall the transfer gear case guard.Recommended oil: See page 10-2
Quantity:
Transfer gear oil and engine oil with
filter replacement:
2.8 L
Tightening torque:
Filler bolt (transfer gear case):
23 Nm (2.3 m·kgf)
U4SH6B.book Page 25 Tuesday, May 27, 2003 4:39 PM

8-37 1. Spark plug cap
1. Capuchon de bougie
1. Tapa de bujía
1. Spark plug wrench
1. Clé à bougie
1. Llave de bujías
EBU11820
Spark plug 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.
For example, a very white center electrode porce-
lain color could indicate an intake air leak or carbu-
retion problem for that cylinder. Do not attempt to
diagnose such problems yourself.
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, you should re-
place the spark plug with one of the proper type.
Standard spark plug:
DR8EA (NGK)
U4SH6B.book Page 37 Tuesday, May 27, 2003 4:39 PM

8-43 1. Air filter element
1.Élément du filtre à air
1. Elemento del filtro de aire
1. Element plate 2. Air filter element
3. Frame
1. Plaque d’élément 2.Élément du filtre à air
3. Armature
1. Placa del elemento 2. Elemento del filtro de aire
3. Bastidor
3. Remove the air filter element.
4. Remove the air filter element from the 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. _6. 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. _7. Inspect the air filter element. If damaged, re-
place it.
8. Apply SAE 10W30 engine oil to the air filter
element.NOTE:_ The air filter element should be wet but not drip-
ping. _
U4SH6B.book Page 43 Tuesday, May 27, 2003 4:39 PM

8-45
9. Apply all-purpose grease to the air filter ele-
ment seat.
10. Install the air filter element on the frame.
11. Install the air filter element.
12. Install the air filter case cover by installing the
screws.
13. Install the seat.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 filter element rubber
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. _
U4SH6B.book Page 45 Tuesday, May 27, 2003 4:39 PM