2010 YAMAHA YFZ450R engine

8-14
8
Before installing the spark plug, the spark plug
gap should be measured with a wire thickness
gauge and, if necessary, adjusted to specification.
Clean the surface of the spark plug gasket and its
mating surface, and then wipe off any grime from
the spark plug threads.
TIPIf a torque wrench is not available when installing
the spark plug, a good estimate of the correct
torque is 1/4–1/2 turn past finger tight. However,
the spark plug should be tightened to the speci-
fied torque as soon as possible. EBU2949AEngine oil and oil filter elementThe engine oil level should be checked before
each ride. In addition, the oil must be changed and
the oil filter element replaced at the intervals spec-
ified in the periodic maintenance and lubrication
chart.
To check the engine oil level
1. Place the ATV on a level surface.
2. Start the engine, warm it up until the engine oil has reached a normal temperature of 60
°C (140 °F), let it continue to idle for ten sec-
onds or more, and then turn the engine off.
Specified spark plug:
NGK/CR8E
1. Spark plug gapSpark plug gap:0.7–0.8 mm (0.028–0.031 in)
Tightening torque:Spark plug:13 Nm (1.3 m·kgf, 9.4 ft·lbf)
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8-15
8
TIPTo achieve the proper engine oil temperature for
an accurate oil level reading, the engine must have
first completely cooled down, and then warmed
up again for several minutes to normal operating
temperature. 3. Remove the engine oil tank filler cap, andwipe the engine oil dipstick off with a clean
rag.
4. Insert the dipstick into the filler hole (without screwing it in), and then remove it again to
check the oil level.TIPThe engine oil should be between the minimum
and maximum level marks.
5. If the engine oil is at or below the minimumlevel mark, add sufficient oil of the recom-
mended type through the engine oil tank filler
hole to raise it to the correct level. NOTICE:
Be sure the engine oil is at the correct lev-
el, otherwise engine damage may result.
[ECB00852]
1. Engine oil tank filler cap
2. Engine oil dipstick
3. Maximum level mark
4. Half-level mark
5. Minimum level mark1
2
3
54
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8-16
8
TIPWhen adding oil, be careful not to overfill the en-
gine oil tank; the oil level rises faster starting from
the half-level mark on the dipstick. 6. Insert the dipstick into the engine oil tank fillerhole, and then tighten the engine oil tank filler
cap. NOTICE: Make sure that the engine oil
tank filler cap is securely tightened; other-
wise, oil may seep out when the engine is
running.
[ECB00363]
To change the engine oil (with or without oil fil-
ter element replacement) 1. Place the ATV on a level surface.
2. Remove the engine guard by removing the bolts. 3. Start the engine, warm it up for several minu-
tes, and then turn it off.
4. Place an oil pan under the engine to collect the used oil.
5. Remove the engine oil tank filler cap, and then remove the engine oil tank drain bolt and
its gasket.
1. Engine guard
2. Bolt
2 21
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8-17
86. Remove the crankcase engine oil drain bolt
and its gasket.
TIPSkip steps 7–10 if the oil filter element is not being
replaced. 7. Remove the oil filter element cover by remov-ing the bolts.
1. Engine oil tank drain bolt
2. Gasket
1
2
1. Crankcase engine oil drain bolt
2. Gasket
1
2
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8-19
811. Install the crankcase engine oil drain bolt, the
engine oil tank drain bolt and their new gas-
ket, and then tighten the bolts to their speci-
fied torques.
12. Refill with the specified amount of the recom- mended engine oil through the engine oil tank
filler hole, and then install and tighten the en-
gine oil tank filler cap.
TIPBe sure to wipe off spilled oil on any parts after the
engine and exhaust system have cooled down. NOTICEECB00301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 CONSERV-
ING II” or higher.
 Make sure that no foreign material enters the
crankcase. 13. Start the engine, and then let it idle for several
minutes while checking it for oil leakage. If oil
is leaking, immediately turn the engine off and
check for the cause.
14. Turn the engine off, and then check the oil level and correct it if necessary.
Tightening torques:
Crankcase engine oil drain bolt:20 Nm (2.0 m·kgf, 14 ft·lbf)
Engine oil tank drain bolt: 20 Nm (2.0 m·kgf, 14 ft·lbf)
Recommended oil: See page 10-1.
Oil quantity: Without oil filter element replacement:1.40 L (1.48 US qt, 1.23 Imp.qt)
With oil filter element replacement: 1.45 L (1.53 US qt, 1.28 Imp.qt)
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8-20
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.
[ECB00372]
EBU29861
CoolantThe 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.
[EWB02671]
EBU27945
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
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8-21
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 lev-
el 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.
[ECB01012]
TIP The radiator fan is automatically switched on or
off according to the coolant temperature in the
radiator. 
If the engine overheats, see page 8-52 for fur-
ther instructions.
EBU26808Cleaning the air filter elementThe 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 rid-
ing 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)
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8-23
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.
[EWB01942]
9. Squeeze the excess solvent out of the sponge material and let it dry. NOTICE: Do
not twist the sponge material when
squeezing it.
[ECB00442]
1. Air filter element
2. Washer
3. Wing bolt
3
2
1
1. Sponge material
2. Air filter element frame
1
2
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