2007 YAMAHA YFZ450 carburetor

Parking ...................................................... 6-5
Parking on a slope .................................... 6-6
Accessories and loading ........................... 6-6
RIDING YOUR ATV ...................................... 7-1
GETTING TO KNOW YOUR ATV.............. 7-2
RIDE WITH CARE AND GOOD
JUDGEMENT ...........................................7-2
BE CAREFUL WHERE YOU RIDE ............ 7-8
TURNING YOUR ATV ............................. 7-12
CLIMBING UPHILL .................................. 7-14
RIDING DOWNHILL................................. 7-16
CROSSING A SLOPE.............................. 7-17
CROSSING THROUGH SHALLOW
WATER ..................................................7-18
RIDING OVER ROUGH TERRAIN .......... 7-20
SLIDING AND SKIDDING ........................ 7-20
WHAT TO DO IF... ................................... 7-21
WHAT TO DO... ....................................... 7-21
PERIODIC MAINTENANCE AND MINOR
REPAIR .......................................................... 8-1
Owner’s manual and tool kit ...................... 8-1
Periodic maintenance and lubrication
chart ........................................................ 8-3
Removing and installing the panel ............ 8-8
Checking the spark plug ............................ 8-9
Engine oil and oil filter element ............... 8-13
Coolant .................................................... 8-19Cleaning the air filter element .................. 8-23
Cleaning the spark arrester ..................... 8-26
Adjusting the carburetor ........................... 8-28
Checking the engine idling speed ............ 8-29
Adjusting the throttle cable free play ........ 8-29
Valve clearance ....................................... 8-30
Checking the front and rear brake pads .. 8-30
Checking the brake fluid level .................. 8-31
Changing the brake fluid .......................... 8-34
Checking the front brake lever free play .. 8-34
Checking the brake pedal position ........... 8-35
Adjusting the parking brake free play ...... 8-36
Brake light switches ................................. 8-37
Adjusting the clutch lever free play .......... 8-38
Drive chain slack ...................................... 8-39
Lubricating the drive chain ....................... 8-41
Checking and lubricating the cables ........ 8-42
Checking and lubricating the brake and
clutch levers ........................................... 8-42
Checking and lubricating the brake and
shift pedals ............................................. 8-43
Checking the wheel bearings ................... 8-43
Lubricating the swingarm pivots .............. 8-44
Lubricating the upper and lower arm
pivots ..................................................... 8-44
Battery ..................................................... 8-45
Replacing the fuse ................................... 8-46
Replacing a headlight bulb ...................... 8-47
Adjusting a headlight beam ..................... 8-49

1-4
1
2
3
4
5
6
7
8
9
10
11

cock is in the “OFF” position. Otherwise, fuel
may leak out of the carburetor or fuel tank.

Gasoline is poisonous. If you should swal-
low some gasoline or inhale a lot of gasoline
vapor, or get some gasoline in your eyes,
seek medical help immediately. If gasoline
spills on your skin, wash with soap and wa-
ter. If gasoline spills on your clothing,
change your clothes.
WARNING

EWB00070
Always operate your ATV in an area with ade-
quate ventilation. Never start or run the engine
in a closed area. Exhaust fumes are poisonousand may cause loss of consciousness and
death within a short time.

4-10
1
2
34
5
6
7
8
9
10
11

The fuel cock lever positions are explained as fol-
lows and shown in the illustrations.
OFF
With the fuel cock lever in this position, fuel will not
flow. Always turn the fuel cock lever to this position
when the engine is not running.
ON
With the fuel cock lever in this position, fuel flows
to the carburetor. Turn the fuel cock lever to this
position when starting the engine and riding.

1. Arrow mark positioned over “OFF”
1. Arrow mark positioned over “ON”

4-17
1
2
34
5
6
7
8
9
10
11

weight and the riding conditions.
WARNING

EWB00430
This shock absorber assembly contains highly
pressurized nitrogen gas. Read and under-
stand the following information before han-
dling the shock absorber assembly.

Do not tamper with or attempt to open the
cylinder assembly.

Do not subject the shock absorber assembly
to an open flame or other high heat source.
This may cause the unit to explode due to ex-
cessive gas pressure.

Do not deform or damage the cylinder in any
way. Cylinder damage will result in poor
damping performance.

Do not dispose of a damaged or worn out
shock absorber assembly yourself. Take the
shock absorber assembly to a Yamaha deal-
er for any service.
Spring preload
1. Remove the seat. (See page 4-11.)
2. Loosen the clamp screw at the carburetor
side, and then disconnect the air intake duct.3. Disconnect the hose, and then remove the air
filter case by removing the bolts.
1. Clamp screw
1

4-20
1
2
34
5
6
7
8
9
10
11

6. Tighten the locknut to the specified torque.
CAUTION:

ECB00080
Always tighten the locknut against the adjust-
ing nut, and then tighten it to the specified
torque.
7. Place the air filter case in the original position,
connect the air intake duct, and then tighten
the clamp screw at the carburetor side.
8. Install the bolts, and then connect the hose.
9. Install the seat.
Rebound damping force
Turn the adjusting screw in direction (a) to increase
the rebound damping force and thereby harden
the damping, and in direction (b) to decrease the
rebound damping force and thereby soften the
damping.
NOTE:

Make sure that the position indicator marks are
aligned when the shock absorber assembly is set Tightening torque:
Locknut:
44 Nm (4.4 m·kgf, 33 ft·lbf)
1. Position indicator marks
2. Rebound damping force adjusting screw
Rebound damping setting:
Minimum (soft):
Adjusting screw fully turned out
Standard:
Adjusting screw 1 1/4 turns out from the
fully turned in position
Maximum (hard):
Adjusting screw fully turned in
21
(b)
(a)

8-5
1
2
3
4
5
6
78
9
10
11

15 Drive chain

Check chain slack and adjust if necessary.

Check rear wheel alignment and correct if necess-
sary.

Clean and lubricate.
√√√√√
16
*
Drive chain rollers


Check for wear and replace if necessary.
√√√
17
*
Chassis fasteners


Make sure that all nuts, bolts, and screws are
properly tightened.
√√√√√
18
*
Shock absorber
assemblies


Check operation and correct if necessary.

Check for oil leakage and replace if necessary.
√√√
19
*
Rear suspension
relay arm and con-
necting arm pivot-
ing points


Check operation and correct if necessary.

Lubricate with lithium-soap-based grease.
√√√√
20
*
Steering shaft


Lubricate with lithium-soap-based grease.
√√√
21
*
Steering system


Check operation and repair or replace if damaged.

Check toe-in and adjust if necessary.
√√√√√
22
*
Engine mount


Check for cracks or other damage, and replace if
necessary.
√√√
23
*
Carburetor


Check starter (choke) operation and correct if nec-
essary.

Check engine idling speed and adjust if neces-
sary.
√√√√
24
*
Crankcase breather
system


Check breather hose for cracks or other damage,
and replace if necessary.
√√√
NO. ITEMCHECK OR MAINTENANCE
JOBINITIAL EVERY
Whichev-
er comes
firstmonth136612
km
(mi)320
(200)1200
(750)2400
(1500)2400
(1500)4800
(3000)
hours 20 75 150 150 300

8-26
1
2
3
4
5
6
78
9
10
11

13. Insert the air filter element into the air filter
case, and then tighten the wing bolt.
14. Install the air filter case cover by hooking the
holders onto the air filter case.
15. 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 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 rubberjoint to the carburetor fittings and the rubber joint
manifold fittings for an air-tight seal. Tighten all fit-
tings securely to avoid the possibility of unfiltered
air entering the engine.
CAUTION:

ECB00460

Make sure that the air filter element is prop-
erly seated in the air filter case.

Never operate the engine with the air filter el-
ement removed. This will allow unfiltered air
to enter the engine, causing rapid engine
wear and possible engine damage. Addition-
ally, operation without the air filter element
will affect carburetor jetting with subsequent
poor performance and possible engine over-
heating.
EBU27700
Cleaning 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

8-28
1
2
3
4
5
6
78
9
10
11

7. 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. Install the purging bolt and tighten it.
WARNING

EWB02380
Never 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.
EBU23940
Adjusting the carburetor
The carburetor should be checked and, if neces-
sary, adjusted at the intervals specified in the peri-
odic maintenance and lubrication chart. The
carburetor is an important part of the engine and
requires very sophisticated adjustment. Therefore,
most carburetor adjustments should be left to a
Yamaha dealer, who has the necessary profes-
sional knowledge and experience. The adjustment
described in the following section, however, may
be performed by the owner as part of routine main-
tenance.
CAUTION:

ECB00480
The carburetor has been set and extensively
tested at the Yamaha factory. Changing these
1. Purging bolt
2. Gasket
1 2