engine YAMAHA YFZ450R 2009 Service Manual

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justed if necessary, before adjusting the throttle ca-
ble free play.
1. Slide the rubber cover back.
2. Loosen the locknut.
3. To increase the throttle cable free play, turn
the throttle cable free play adjusting bolt in di-
rection (a). To decrease the throttle cable free
play, turn the adjusting bolt in direction (b).
4. Tighten the locknut.
5. Slide the rubber cover to its original position.
EBU24060
Valve clearance
The valve clearance changes with use, resulting in
improper air-fuel mixture and/or engine noise. To
prevent this from occurring, the valve clearance
must be adjusted by a Yamaha dealer at the inter-
vals specified in the periodic maintenance and lu-
brication chart.
EBU24130
Checking the front and rear brake pads
The front and rear brake pads must be checked for
wear at the intervals specified in the periodic main-
tenance and lubrication chart.
EBU29560
Front brake pads
Each brake pad is provided with wear indicator
grooves, which allow you to check the brake pad
wear without having to disassemble the brake. To
check the brake pad wear, check the wear indica-
tor grooves. If a brake pad has worn to the point
that the wear indicator grooves have almost disap-
peared, have a Yamaha dealer replace the brake
pads as a set.
1. Rubber cover
2. Throttle cable free play adjusting bolt
3. Locknut
4. Throttle lever free play
4 2 1
3
(a)
(b)

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NOTICE

ECB00570
To prevent damaging the O-rings, do not clean
the drive chain with steam cleaners, high-pres-
sure washers or inappropriate solvents.
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive chain with a
special O-ring chain lubricant.
NOTICE

ECB00580
Do not use engine oil or any other lubricants
for the drive chain, as they may contain sub-
stances that could damage the O-rings.
EBU24900
Checking and lubricating the cables
The operation and the condition of all control ca-
bles should be checked before each ride, and the
cables and cable ends should be lubricated if nec-
essary. If a cable is damaged or does not move
smoothly, have a Yamaha dealer check or replace
it.
WARNING
EWB02130
Inspect cables frequently and replace if dam-
aged. Corrosion can result when the cable
sheaths become damaged, and cables can
also become frayed or kinked, which could re-
strict the operation of controls and lead to an
accident or injury.
EBU24922
Checking and lubricating the brake and
clutch levers
The operation of the brake and clutch levers
should be checked before each ride, and the lever
pivots should be lubricated if necessary.
Recommended lubricant:
Engine oil
Recommended lubricants:
Brake lever:
Silicone grease
Clutch lever:
Lithium-soap-based grease

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EBU27691
Troubleshooting charts
Starting problems or poor engine performance
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the compression.
Supply fuel.
The engine does not start.
Check the compression.
Operate the electric starter.2. Compression
There is compression.
There is no compression.
Check the ignition.
Have a Yamaha dealer
check the ATV.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the ATV.
The engine does not start.
Have a Yamaha dealer
check the ATV.
The engine does not start.
Check the battery.
Operate the electric starter.4. Battery
The engine turns over 
quickly.
The engine turns over 
slowly.
The battery is good.Check the battery lead connections,
and charge the battery if necessary.
DryWet
Operate the electric starter.

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Engine overheating
WARNING

EWB02290
Wait for the engine and radiator to cool before removing the radiator cap. You could be burned by
hot fluid and steam blown out under pressure. Always put a thick rag over the cap when opening.
Allow any remaining pressure to escape before completely removing the cap.
TIP

If coolant is not available, tap water can be temporarily used instead, provided that it is changed to the rec-
ommended coolant as soon as possible.
Wait until the
engine has cooled.
Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer check
and repair the cooling system.Add coolant. (See TIP.)
Start the engine. If the engine overheats again, have a
Yamaha dealer check and repair the cooling system.
There is
leakage.
There is
no leakage.

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EBU25860
CLEANING AND STORAGE
EBU25900
Cleaning
Frequent, thorough cleaning of your ATV will not
only enhance its appearance but will improve its
general performance and extend the useful life of
many components.
1. Before cleaning the ATV:
a. Block off the end of the exhaust pipe to
prevent water entry. A plastic bag and
strong rubber band may be used.
b. Make sure the spark plug and all filler caps
are properly installed.
2. If the engine case is excessively greasy, apply
degreaser with a paint brush. Do not apply de-
greaser to the chain, sprockets or wheel ax-
les.
3. Rinse the dirt and degreaser off with a garden
hose. Use only enough pressure to do the job.
NOTICE

ECB00710
Excessive water pressure may cause water
seepage and deterioration of wheel bearings,
brakes, transmission seals and electrical de-
vices. Many expensive repair bills have result-ed from improper high-pressure detergent
applications such as those available in coin-
operated car washers.
4. Once most of the dirt has been hosed off,
wash all surfaces with warm water and mild,
detergent-type soap. An old toothbrush or bot-
tle brush is handy for hard-to-reach places.
5. Rinse the ATV off immediately with clean wa-
ter and dry all surfaces with a chamois, clean
towel or soft absorbing cloth.
6. Dry the chain and lubricate it to prevent it from
rusting.
7. Clean the seat with a vinyl upholstery cleaner
to keep the cover pliable and glossy.
8. Automotive type wax may be applied to all
painted and chrome plated surfaces. Avoid
combination cleaner-waxes. Many contain
abrasives which may mar the paint or protec-
tive finish. When finished cleaning, start the
engine and let it idle for several minutes.
WARNING

EWB02310
Wet brakes may have reduced stopping ability,

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increasing the chance of an accident. Test the
brakes after washing. Apply the brakes several
times at slow speeds to let friction dry out the
linings.
EBU27260
Storage
Short-term
Always store your ATV in a cool, dry place and, if
necessary, protect it against dust with a porous
cover.
NOTICE

ECB00720

Storing the ATV in a poorly ventilated room
or covering it with a tarp while it is still wet,
will allow water and humidity to seep in and
cause rust.

To prevent corrosion, avoid damp cellars,
stables (because of the presence of ammo-
nia) and areas where strong chemicals are
stored.
Long-term
Before storing your ATV for several months:
1. Follow all the instructions in the “Cleaning”section of this chapter.
2. Fill up the fuel tank and add fuel stabilizer (if
available) to prevent the fuel from deteriorat-
ing.
3. Perform the following steps to protect the cyl-
inder, piston rings, etc. from corrosion.
a. Remove the spark plug cap and spark
plug.
b. Pour a teaspoonful of engine oil into the
spark plug bore.
c. Install the spark plug cap onto the spark
plug, and then place the spark plug on the
cylinder head so that the electrodes are
grounded. (This will limit sparking during
the next step.)
d. Turn the engine over several times with
the starter. (This will coat the cylinder wall
with oil.)
e. Remove the spark plug cap from the spark
plug, and then install the spark plug and
the spark plug cap.
4. Lubricate all control cables and the pivotingSpecified amount:
7.5 ml of stabilizer to each liter of fuel (or 1 oz
of stabilizer to each gallon of fuel)

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EBU25960
SPECIFICATIONS
EBU2597D
Dimensions:
Overall length:
1795 mm (70.7 in)
Overall width:
1240 mm (48.8 in)
Overall height:
1065 mm (41.9 in)
Seat height:
810 mm (31.9 in)
Wheelbase:
1270 mm (50.0 in)
Ground clearance:
235 mm (9.3 in)
Minimum turning radius:
3600 mm (142 in)
Weight:
With oil and fuel:
184.0 kg (406 lb)
Noise and vibration level:
Noise level (77/311/EEC):
84.5 dB(A) (EUR)
Vibration on seat (EN1032, ISO5008):
Will not exceed 0.5 m/s
2

(EUR)
Vibration on handlebar (EN1032, ISO5008):
Will not exceed 2.5 m/s
2

(EUR)
Engine:
Engine type:
Liquid cooled 4-stroke, DOHC
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
449.0 cm
3

Bore
×
stroke:
95.0
×
63.4 mm (3.74
×
2.50 in)
Compression ratio:
11.60 :1
Starting system:
Electric starter
Lubrication system:
Dry sump

Engine oil:
Type:
SAE 5W-30 or SAE 10W-30 or SAE 10W-40 or SAE
15W-40 or SAE 20W-40 or SAE 20W-50

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Recommended engine oil grade:
API service SG type or higher, JASO standard MA
Engine 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)
Cooling system:
Coolant reservoir capacity (up to the maximum level mark):
0.25 L (0.26 US qt, 0.22 Imp.qt)
Radiator capacity (including all routes):
1.25 L (1.32 US qt, 1.10 Imp.qt)
Air filter:
Air filter element:
Wet element
Fuel:
Recommended fuel:
Premium unleaded gasoline only
Fuel tank capacity:
10.0 L (2.64 US gal, 2.20 Imp.gal)
Fuel reserve amount:
3.4 L (0.90 US gal, 0.75 Imp.gal)
Fuel injection:
Throttle body:
Type/quantity:
42EHS/1
Spark plug (s):
Manufacturer/model:
NGK/CR8E
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
Clutch:
Clutch type:
Wet, multiple-disc
Transmission:
Primary reduction system:
Spur gear
Primary reduction ratio:
61/23 (2.652)
Secondary reduction system:
Chain drive
Secondary reduction ratio:
38/14 (2.714)
Transmission type:
Constant mesh 5-speed
-20 -10 0
1020 304050 ˚C
SAE 15W-40
SAE 20W-40SAE 20W-50
SAE 10W-40
SAE 5W-30
SAE 10W-30

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Operation:
Right hand operation
Recommended fluid:
DOT 4
Rear brake:
Type:
Single disc brake
Operation:
Right foot operation
Recommended fluid:
DOT 4
Front suspension:
Type:
Double wishbone
Spring/shock absorber type:
Coil spring/gas-oil damper
Wheel travel:
250 mm (9.9 in)
Rear suspension:
Type:
Swingarm (link suspension)
Spring/shock absorber type:
Coil spring/gas-oil damper
Wheel travel:
280 mm (11.0 in)
Electrical system:
Ignition system:
TCI (digital)
Charging system:
AC magneto
Battery:
Model:
YTZ-7S
Voltage, capacity:
12 V, 6.0 Ah
Headlight:
Bulb type:
Krypton bulb
Bulb voltage, wattage
×× × ×
quantity:
Headlight:
12 V, 30/30 W
×
2
Tail/brake light:
LED
Neutral indicator light:
LED
Fuel level warning light:
LED
Coolant temperature warning light:
LED
Engine trouble warning light:
LED
Fuses:
Main fuse:
20.0 A

INDEX
A
Accessories and loading ................................................ 6-5
Air filter element, cleaning ............................................ 8-23
B
Battery .......................................................................... 8-43
Brake and clutch levers, checking and lubricating ....... 8-40
Brake fluid, changing.................................................... 8-32
Brake fluid level, checking............................................ 8-30
Brake lever ..................................................................... 4-6
Brake lever free play, checking the front ...................... 8-32
Brake light switches ..................................................... 8-35
Brake pads, checking the front and rear ...................... 8-29
Brake pedal .................................................................... 4-7
Brake pedal, checking and lubricating ......................... 8-41
Brake pedal position, checking .................................... 8-33
Brakes, front and rear .................................................... 5-4
C
Cables, checking and lubricating ................................. 8-40
Chassis fasteners........................................................... 5-8
Cleaning ......................................................................... 9-1
Clutch lever .................................................................... 4-6
Clutch lever free play, adjusting ................................... 8-36
Coolant ................................................................. 5-4
,
8-19
Coolant temperature warning light ................................. 4-2
D
Drive chain ..................................................................... 5-5Drive chain, lubricating ................................................. 8-39
Drive chain slack .......................................................... 8-37
E
Engine break-in .............................................................. 6-4
Engine oil ....................................................................... 5-4
Engine oil and oil filter element .................................... 8-14
Engine, start ................................................................... 6-1
Engine stop switch ......................................................... 4-3
Engine trouble warning light ........................................... 4-3
F
Fuel ........................................................................ 4-9
,
5-4
Fuel level warning light................................................... 4-2
Fuel tank cap.................................................................. 4-8
Fuse, replacing............................................................. 8-46
H
Handlebar position, adjusting ....................................... 4-24
Handlebar switches ........................................................ 4-3
Headlight beam, adjusting............................................ 8-48
Headlight bulb, replacing.............................................. 8-46
I
Identification numbers .................................................. 11-1
Indicator light and warning lights .................................... 4-2
Instruments, lights and switches .................................... 5-8
K
Key identification number ............................................. 11-1