Page 136 of 452
5-13
EBU10842
Engine oil
Make sure the engine oil is at the specified level.
Add oil as necessary. (See page 8-23.)CAUTION:_
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
CONSERVING II” or higher.
Make sure that no foreign material enters
the crankcase.
_
Recommended engine oil type and quantity:
See page 10-2.
U5TG61.book Page 13 Friday, April 2, 2004 11:28 AM
Page 292 of 452

8-25 1. Engine oil tank 2. Engine oil tank filler cap
3. Dipstick 4. Maximum level mark
5. Minimum level mark 6. Engine oil filler cap
1. Réservoir d’huile de moteur
2. Bouchon de remplissage de l’huile de moteur
3. Jauge
4. Repère de niveau maximum
5. Repère de niveau minimum
6. Bouchon de remplissage d’huile de moteur
1. Depósito de aceite de motor
2. Tapa de relleno del depósito de aceite de motor
3. Varilla de medición
4. Marca de nivel máximo
5. Marca de nivel mínimo
6. Tapa del filtro de aceite de motor
3. Remove the engine oil tank filler cap, wipe
the dipstick clean with a clean rag, insert it
back into the filler hole (without screwing it
in), and then remove it again to check the oil
level.NOTE:_ The engine oil should be between the minimum
and maximum level marks. _4. If the engine oil is below the minimum level
mark, add sufficient oil of the recommended
type through the engine oil tank filler hole to
raise it to the correct level.NOTE:_ When adding oil, be careful not to overfill the en-
gine oil tank; the oil level rises faster starting from
the half-level-portion on the dipstick. _5. Insert the dipstick into the engine oil tank filler
hole, and then tighten the engine oil tank filler
cap.
U5TG61.book Page 25 Friday, April 2, 2004 11:28 AM
Page 352 of 452

8-85 1. Brake fluid reservoir cover 2. Bolt (× 2)
1. Cache du réservoir de liquide de frein
2. Boulon (× 2)
1. Cubierta del depósito de líquido de frenos
2. Perno (× 2)
Observe these precautions:
When checking the brake fluid level, make sure
the top of the brake fluid reservoir is level.
Use only the designated quality brake fluid, oth-
erwise, the rubber seals may deteriorate, caus-
ing leakage and poor brake performance.
Refill with the same type of brake fluid. Mixing
fluids may result in a harmful chemical reaction
and lead to poor brake performance.
Be careful that water does not enter the brake
fluid reservoir when refilling. Water will signifi-
cantly lower the boiling point of the fluid and
may result in vapor lock.
Brake fluid may deteriorate painted surfaces or
plastic parts. Always clean up spilled fluid im-
mediately.
Have a Yamaha dealer check the cause if the
brake fluid level goes down. Recommended brake fluid: DOT 4
U5TG61.book Page 85 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
Page 431 of 452
10-2
10
Engine oil:
Type
Recommended engine oil classification API Service SE, SF, SG type or higher
Quantity:
Without oil filter element replacement
With oil filter element replacement1.75 L
1.85 L MODEL YFZ450
-20˚ -10˚ 0˚
10˚20˚ 30˚40˚50˚C
10W/30
15W/4020W/4020W/50
10W/40
5W/30
CAUTION:In order to prevent clutch slippage (since the en-
gine 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 CONSERVING II” or higher.
U5TG61.book Page 2 Friday, April 2, 2004 11:28 AM
Page 433 of 452
10-4
Gear ratio:
1st
2nd
3rd
4th
5th29/12 (2.416)
27/14 (1.928)
25/16 (1.562)
23/18 (1.277)
21/20 (1.050)
Chassis:
Frame type
Caster angle
TrailSteel tube
5.0
°
21.0 mm
Tire:
Type
Size: Front
Size: RearTubeless
AT21 ×
7R-10
AT20 ×
10R-9
Brake:
Front brake type
Operation
Rear brake type
OperationDual disc brake
Right hand operation
Single disc brake
Right foot operation
Suspension:
Front
RearDouble wishbone
Swingarm (link suspension)
Shock absorber:
Front
RearCoil spring/gas-oil damper
Coil spring/gas-oil damper MODEL YFZ450
U5TG61.book Page 4 Friday, April 2, 2004 11:28 AM