Page 15 of 452

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
Page 128 of 452
5-5
EBU11670
Front and rear brakes
Brake lever and brake pedal
Check that there is no free play in the brake le-
ver. If there is free play, have a Yamaha dealer
inspect the brake system.
Check for correct brake pedal height. (See
page 8-91.) If the pedal height is incorrect,
have a Yamaha dealer adjust it.
Check the operation of the brake lever and
brake pedal. They should move smoothly and
there should be a firm feeling when the brakes
are applied. If not, have a Yamaha dealer in-
spect the brake system.
Brake fluid level
Check the brake fluid level. Add fluid if necessary.
(See pages 8-83–8-87.)
Recommended brake fluid: DOT 4
U5TG61.book Page 5 Friday, April 2, 2004 11:28 AM
Page 358 of 452
8-91 a. Brake pedal position
a. Position de la pédale de frein
a. Posición del pedal del freno
EBU10790
Brake pedal height adjustment
The top of the brake pedal should be positioned
11.7 mm below the top of the footrest. If not, have
a Yamaha dealer adjust it.
WARNING
_ Operating with improperly serviced or adjust-
ed brakes could cause loss of braking ability,
which could lead to an accident. After servic-
ing:
Make sure the brakes operate smoothly
and that the brake pedal position is cor-
rect.
Make sure the brakes do not drag.
Make sure the brakes are not spongy. All
air must be bled from the brake system.
Replacement of brake components requires
professional knowledge. These procedures
should be performed by a Yamaha dealer.
_
U5TG61.book Page 91 Friday, April 2, 2004 11:28 AM
Page 430 of 452
10-1
EBU04280
1-SPECIFICATIONS
MODEL YFZ450
Dimension:
Overall length
Overall width
Overall height
Seat height
Wheel base
Ground clearance
Minimum turning radius1,840 mm
1,170 mm
1,090 mm
800 mm
1,280 mm
255 mm
3,500 mm
Basic weight:
With oil and full fuel tank 169.0 kg
Engine:
Type
Cylinder arrangement
Displacement
Bore
× stroke
Compression ratio
Starting system
Lubrication systemLiquid-cooled, 4-stroke, DOHC
Forward inclined single cylinder
439.0 cm
3
95.0
× 62.0 mm
11.90 : 1
Electric starter
Dry sump
U5TG61.book Page 1 Friday, April 2, 2004 11:28 AM