2011 YAMAHA YFZ450R Owners Manual

8-19
8 15. Install the engine guard by installing the bolts,
and then tighten them to the specified torque.
NOTICE: Be sure to apply LOCTITE
® to the
engine guard bolts before installing them.
[ECB00371]
EBU29860
Coolant The coolant level should be checked before each
ride. In addition, the coolant must be changed at
the intervals specified in the periodic maintenance
and lubrication chart. Have a Yamaha dealer
change the coolant. WARNING! Never attempt to
remove the radiator cap when the engine is
hot.
[EWB02670]
EBU27941
To check the coolant level
1. Place the ATV on a level surface.
TIPThe coolant level must be checked on a cold en-
gine since the level varies with engine tempera-
ture.2. Check the coolant level in the coolant reser-
voir.TIPThe coolant should be between the minimum and
maximum level marks.
Tightening torque:
Engine guard bolt:
7 Nm (0.7 m·kgf, 5.1 ft·lbf)
1. Coolant reservoir cap
2. Maximum level mark
3. Minimum level mark
1
2
3
U18P64E0.book Page 19 Thursday, May 13, 2010 6:00 PM

8-20
83. If the coolant is at or below the minimum level
mark, remove the coolant reservoir cap, add
coolant or distilled water to the maximum level
mark, and then install the reservoir cap.
NOTICE: If coolant is not available, use
distilled water or soft tap water instead. Do
not use hard water or salt water since they
are harmful to the engine. If water has
been used instead of coolant, replace it
with coolant as soon as possible, other-
wise the cooling system will not be pro-
tected against frost and corrosion. If water
has been added to the coolant, have a
Yamaha dealer check the antifreeze con-
tent of the coolant as soon as possible,
otherwise the effectiveness of the coolant
will be reduced.
[ECB01011]
TIP
The radiator fan is automatically switched on or
off according to the coolant temperature in the
radiator.

If the engine overheats, see page 8-50 for fur-
ther instructions.EBU26806Cleaning the air filter element The air filter element should be cleaned at the in-
tervals specified in the periodic maintenance and
lubrication chart. Clean or, if necessary, replace
the air filter element more frequently if you are
riding in unusually wet or dusty areas.TIPThere is a check hose at the bottom of the air filter
case. If dust or water collects in this hose, empty
the hose and clean the air filter element and air fil-
ter case.
Coolant reservoir capacity (up to the maxi-
mum level mark):
0.25 L (0.26 US qt, 0.22 Imp.qt)
U18P64E0.book Page 20 Thursday, May 13, 2010 6:00 PM

8-21
8 1. Place the ATV on a level surface.
2. Remove the seat. (See page 4-10.)
3. Remove the air filter case cover by unhooking
the holders.4. Fully loosen the wing bolt.
5. Remove the air filter element together with the
wing bolt and washer.
1. Air filter case check hose
1
1. Air filter case cover
2. Air filter case cover holder
1
2
U18P64E0.book Page 21 Thursday, May 13, 2010 6:00 PM

8-22
86. Remove the wing bolt and washer from the air
filter element.
7. Remove the sponge material from the air filter
element frame.8. Wash the sponge material gently but thor-
oughly in solvent. WARNING! Always use
parts cleaning solvent to clean the sponge
material. Never use low-flash-point sol-
vents or gasoline to clean the sponge ma-
terial because the engine could catch fire
or explode.
[EWB01941]
9. Squeeze the excess solvent out of the sponge
material and let it dry. NOTICE: Do not twist
the sponge material when squeezing it.
[ECB00441]
1. Air filter element
2. Washer
3. Wing bolt
3
2
1
1. Sponge material
2. Air filter element frame
1 2
U18P64E0.book Page 22 Thursday, May 13, 2010 6:00 PM

8-23
8 10. Check the sponge material and replace it if
damaged.
11. Apply Yamaha foam air filter oil or other qual-
ity foam air filter oil to the sponge material.
TIPThe sponge material should be wet but not drip-
ping.12. Pull the sponge material over the air filter ele-
ment frame.
13. Apply all-purpose grease to the air filter ele-
ment seat.14. Install the washer onto the air filter element
frame, and then insert the wing bolt into the
hole in the air filter element frame. NOTICE:
Be sure to install the washer with its
curved side facing outward as shown.
[ECB00453]
1. Air filter element seat
1
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8-24
815. Insert the air filter element into the air filter
case, and then tighten the wing bolt. NOTICE:
Make sure that the air filter element is
properly seated in the air filter case. Never
operate the engine with the air filter ele-
ment removed. This will allow unfiltered air
to enter the engine, causing rapid engine
wear and possible engine damage. Addi-
tionally, operation without the air filter ele-
ment will affect the fuel injection system
with subsequent poor performance and
possible engine overheating.
[ECB00761]
16. Install the air filter case cover by hooking the
holders onto the air filter case.17. Install the seat.
TIPThe air filter element should be cleaned every 20–
40 hours. It should be cleaned and lubricated more
often if the ATV is operated in extremely dusty ar-
eas. Each time the air filter element maintenance
is performed, check the air inlet of the air filter case
for obstructions. Check the air filter case rubber
joint to the throttle body and the rubber joint mani-
fold fittings for an air-tight seal. Tighten all fittings
securely to avoid the possibility of unfiltered air en-
tering the engine.EBU27702Cleaning the spark arrester Select a well-ventilated area free of combustible
materials and make sure the exhaust and muffler
are cool.
1. Remove the bolt.
1. Washer
1
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8-25
8 2. Remove the tailpipe by pulling it out of the
muffler.
3. Tap the tailpipe lightly, and then use a wire
brush to remove any carbon deposits from the
spark arrester portion of the tailpipe and inside
of the tailpipe housing.4. Insert the tailpipe into the muffler and align the
bolt holes.
5. Install the bolt and tighten it to the specified
torque.
6. Remove the purging bolt and the gasket.
1. Bolt
2. Tailpipe
1
2
1. Tailpipe
2. Spark arresterTightening torque:
Tailpipe bolt:
8 Nm (0.8 m·kgf, 5.8 ft·lbf)
1
2
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8-26
87. Start the engine and rev it up approximately
twenty times while momentarily creating ex-
haust system back pressure by blocking the
end of the muffler with a shop towel.
8. Stop the engine and allow the exhaust pipe to
cool.
9. Check the gasket for damage, and replace it if
necessary.
10. Install the gasket and the purging bolt, and
then tighten the bolt to the specified torque.
WARNING
EWB02380Never run the engine in an enclosed area when
purging the spark arrester, otherwise it could
cause injury to the eyes, burns, carbon monox-
ide poisoning, possibly leading to death, and
start a fire.
Always let the exhaust system cool prior to
touching exhaust components.
Always wear eye protection, and make sure
no one is behind the ATV.
Make sure there are no combustible materi-
als in the area.EBU29701Adjusting the throttle lever free play The throttle lever free play should be checked and,
if necessary, adjusted at the intervals specified in
the periodic maintenance and lubrication chart.
1. Purging bolt
2. Gasket
2
1
Tightening torque:
Purging bolt:
27 Nm (2.7 m·kgf, 20 ft·lbf)
U18P64E0.book Page 26 Thursday, May 13, 2010 6:00 PM