Yamaha 2008 Yamaha YZ450F Motocross Motorcycles

1.8 gal

Fuel Capacity

219 lb

Dry Weight

14.7 in

Ground Clearance

58.8 in

Wheelbase

38.9 in

Seat Height

51.4 in

Height

32.5 in

Width

86.4 in

Length

 

Dimensions

120/80-19-62M

Tires/Rear

80/100-21-51M

Tires/Front

Hydraulic single disc brake, 245mm

Brakes/Rear

Hydraulic single disc brake, 250mm

Brakes/Front

Fully adjustable single shock; 12.3-in travel

Suspension/Rear

Speed-Sensitive System inverted fork; fully adjustable, 11.8-in travel

Suspension/Front

 

Chassis

Chain Drive

Final Drive

Constant-mesh 5-speed; multiplate wet clutch

Transmission

CDI

Ignition

FCR-MX39 x 1

Carburetion

12.3:1

Compression Ratio

95.0 x 63.4mm

Bore x Stroke

449cc liquid-cooled DOHC 4-stroke; 5 titanium valves

Type

 

Description:
Revisedintake port shapes, and revised intake and exhaust cam profilesincrease combustion efficiency for improved torque and throttleresponse in the low- to mid-rpm range.
 Micron-level adjustment ofpiston external diameter minimizes piston-to-cylinder clearance forreduced vibration and mechanical noise.
Adjustment of gear backlash between clutch primary gears and balancer gears achieves further mechanical noise reduction.
 A new, larger-diameter titanium exhaust header with revised taper characteristics enhances exhaust efficiency.
 Firstpunched cone muffler ever on a production bike allows 35 percent lengthreduction and 270-gram weight reduction while meeting AMA noiseregulations.
 Matte black crankcase covers: light, strong and cool-looking.
 Steeringhead pipe and steering stem are 5mm shorter; lower forged triplesteering clamp is lighterfor enhanced handling feel. Swingarm pivotstiffness is revised to complement front-end changes and furtherlighten and improve steering/handling.
 Changes to the shape of the outer fork tubes and revised internals result in improved damping and a smoother ride.
 Optimized linkage ratio provides a smoother ride and enhanced rear wheel traction.
 New,YZ250F-style, front-brake caliper (-220 grams) and a lighter discremove unsprung weight and provide excellent stopping power. A new axleand collar remove additional weight.
A 120/80-19 rear Dunlop D756 knobby replaces the 110/90-19 for even more traction. A D742FA replaces the D739FAL front tire.
Wider footpegs provide excellent boot traction and rider comfort.

SPECIFICATIONS :

Engine

Yamaha 2008 Yamaha YZ450F Motocross