2005 YAMAHA YFZ450 carburetor

OPERATION ............................................6-1
Starting a cold engine ...........................6-3
Starting a warm engine .........................6-9
Warming up...........................................6-9
Shifting ................................................6-11
To start out and accelerate .................6-13
To decelerate ......................................6-17
Engine break-in ...................................6-19
Parking ................................................6-23
Parking on a slope ..............................6-25
Accessories and loading .....................6-29
RIDING YOUR ATV..................................7-1
Getting to know your ATV .....................7-3
Ride with care and good judgement .....7-5
Be careful where you ride ...................7-27
Turning your ATV ................................7-41
Climbing uphill.....................................7-47
Riding downhill ....................................7-57
Crossing a slope .................................7-61
Crossing through shallow water ..........7-65
Riding over rough terrain ....................7-69
Sliding and skidding ............................7-71
What to do if ........................................7-75
What to do...........................................7-75
67
PERIODIC MAINTENANCE AND
ADJUSTMENT ......................................... 8-1
Owner’s manual and tool kit ................. 8-3
Periodic maintenance/lubrication.......... 8-7
Panel removal and installation............ 8-17
Engine oil and oil filter element........... 8-23
Cooling system ................................... 8-41
Changing the coolant.......................... 8-45
Spark plug inspection ......................... 8-53
Air filter element cleaning ................... 8-65
Carburetor adjustment ........................ 8-73
Idle speed adjustment ........................ 8-75
Valve clearance adjustment ............... 8-75
Throttle lever adjustment .................... 8-77
Front brake pad inspection ................. 8-79
Rear brake pad inspection.................. 8-81
Brake fluid level inspection ................. 8-83
Brake fluid replacement ...................... 8-87
Front brake lever free play.................. 8-89
Brake pedal height adjustment ........... 8-91
Parking brake adjustment ................... 8-93
Adjusting the rear brake light switch ... 8-97
Clutch lever free play adjustment ....... 8-99
Drive chain slack check .................... 8-101
Drive chain slack adjustment ............ 8-103
Lubricating the drive chain................ 8-107
Cable inspection and lubrication....... 8-111
8
U5TG61.book Page 2 Friday, April 2, 2004 11:28 AM

2-17
WARNING
_

Always turn off the engine when refueling.


Do not refuel immediately after the engine
has been running and is still very hot.


Do not spill gasoline on the engine or ex-
haust pipe/muffler when refueling. Never
refuel while smoking or in the vicinity of
sparks, open flames, or other sources of
ignition such as the pilot lights of water
heaters and clothes dryers. Gasoline can
catch fire. You could be burned.


When transporting the machine in another
vehicle, be sure it is kept upright and that
the fuel cock is in the “OFF” position. Oth-
erwise, 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 gaso-
line vapor, or get some gasoline in your
eyes, see your doctor immediately. If gaso-
line spills on your skin, wash with soap
and water. If gasoline spills on your cloth-
ing, change your clothes.
_
U5TG61.book Page 17 Friday, April 2, 2004 11:28 AM

4-23
EBU00930
Fuel cock
The fuel cock supplies fuel from the fuel tank to the
carburetor.
The fuel cock has three positions.
OFF: With the lever in this position, fuel will not
flow. Always turn the lever to this position
when the engine is not running.
ON: With the lever in this position, fuel flows to
the carburetor. Normal riding is done with
the lever in this position.
RES: This indicates reserve. If you run out of fuel
while riding, turn the lever to this position.
THEN FILL THE FUEL TANK AT THE
FIRST OPPORTUNITY. After refuelling, re-
turn the fuel cock lever to the “ON” position.
U5TG61.book Page 23 Friday, April 2, 2004 11:28 AM

4-41 1. Clamp screw
1. Vis de collier
1. Tornillo de la abrazadera
1. Hose
1. Durit
1. Manguera
Adjust the spring preload as follows.
1. Remove the seat. (See page 4-27 for seat re-
moval and installation procedures.)
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.
U5TG61.book Page 41 Friday, April 2, 2004 11:28 AM

4-45 A. Spring length
A. Longueur du ressort
A. Longitud del muelle
7. Tighten the locknut to the specified torque.CAUTION:_ Always tighten the locknut against the adjust-
ing nut, and then tighten it to the specified
torque. _8. Place the air filter case in the original position,
connect the air intake duct, and then tighten
the clamp screw at the carburetor side.
9. Install the bolts, and then connect the hose.
10. Install the seat.Measurement
A:
Installed length:
Minimum (hard): 237 mm
Standard: 244 mm
Maximum (soft): 251 mm
Tightening torque:
Locknut:
45 Nm (4.5 m·kgf)
U5TG61.book Page 45 Friday, April 2, 2004 11:28 AM

8-7
EBU02621
PERIODIC MAINTENANCE/LUBRICATION
NOTE:_

For ATVs not equipped with an odometer or an hour meter, follow the month maintenance intervals.


For ATVs equipped with an odometer or an hour meter, follow the km (mi) or hours maintenance in-
tervals. However, keep in mind that if the ATV isn’t used for a long period of time, the month mainte-
nance intervals should be followed.
_
ITEM ROUTINEWhichever
comes firstINITIAL EVERY
month136612
km
(mi)320
(200)1,200
(750)2,400
(1,500)2,400
(1,500)4,800
(3,000)
hours 20 75 150 150 300
Valves*Check valve clearance.
Adjust if necessary.
Cooling systemCheck for coolant leakage.
Repair if necessary.
Replace coolant every 24 months.Spark plugCheck condition.
Adjust gap and clean.
Replace if necessary.Air filter elementClean.
Replace if necessary.Every 20–40 hours
(More often in wet or dusty areas.)
Carburetor*Check starter (choke) operation.
Adjust engine idling speed.Crankcase breather
system*Check breather hose for cracks or damage.
Replace if necessary.Exhaust system*Check for leakage.
Tighten if necessary.
Replace gasket if necessary.Fuel line*Check fuel hose for cracks or damage.
Replace if necessary.Engine oil
Replace (Warm engine before draining).U5TG61.book Page 7 Friday, April 2, 2004 11:28 AM

8-55 1. Bolt
1. Boulon
1. Perno
1. Spark plug cap
1. Capuchon de bougie
1. Tapa de bujía
4. Pull the panel backward, and then remove it.
5. Install the fuel tank cap by turning it clock-
wise.
6. Remove the bolt, lift the rear of the fuel tank,
and then tilt it back.
WARNING
_ Before lifting the fuel tank, make sure that the
fuel cock is in the “OFF” position and the fuel
tank cap is securely tightened. Otherwise, fuel
may leak out of the carburetor or fuel tank. _7. Remove the spark plug cap.
U5TG61.book Page 55 Friday, April 2, 2004 11:28 AM

8-71
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 intake duct between
the air filter case and the carburetor and the mani-
fold fittings for an airtight seal. Tighten all fittings
securely to avoid the possibility of unfiltered air en-
tering the engine. _CAUTION:_ 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. Additionally, op-
eration without the air filter element will affect
carburetor jetting with subsequent poor per-
formance and possible engine overheating. _
U5TG61.book Page 71 Friday, April 2, 2004 11:28 AM