2008 Yamaha YZ450F

– 2008 Yamaha YZ450F

2008 Yamaha YZ450F

YZ450F… taking MX1 performance to a new level.

The best just keeps getting better. The bike that started the 4-stroke revolution benefits from a host of engine and chassis improvements for 2008. The intake tract has been revised, as have the cams, header pipe and stylish new “shorty” type muffler. Even the fame has gone under the microscope and now features a shorter steering head for better balanced handling and reduced weight. The bike that started the trend just keeps on getting better.

Our most powerful, most flickable 450 ever. The bike that started the four stroke revolution keeps moving forward with chassis and engine refinements that ensure the five titanium valved 2008 Yamaha YZ450F remains at the head of the open class pack.

Some times it can be the little things that in the end make the difference.

We have changed a number of big items on the new ’08 YZ450F including the steering head area of the frame, but we didn’t forget the little details either. Extra wide footpegs, new fork protectors, new upper and lower triple clamps to mention a few. Heck, we even changed the width of the rear tire for improved traction. If you are serious about racing … the 2008 YZ450F is the bike for you.

FEATURES:

Revised liquid-cooled, 449cc, DOHC, 5-valve, 4-stroke, single with titanium valves delivers a broad power curve with a great over-rev capacity. Numerous improvements provide more low to mid rpm power and an improvement in overall powerful feeling.

Compact cylinder head design utilizes lightweight titanium valves and load-reduced springs reduce reciprocating mass for less friction, faster-revving and smoother-hitting power delivery across the rev range.

Revised intake port shape provides improved “breathing efficiency” for more complete cylinder filling and more engine power in the low to mid rpm range.

Revised intake and exhaust camshafts profiles have been optimized. The intake valve timing and overlap has been changed while the working angle and lift of the exhaust cam has been modified. The result is improved torque output in the low to mid rpm range.

The cylinder features a ceramic composite coating which insures faster, more uniform heat dissipation, reduced friction and a longer service life.

Special cylinder design features cutaways that allow the air “trapped” under the piston to enter a side chamber (or cutaway) to reduce horsepower-robbing “pumping losses.”

The crankcase also utilizes cutaways to reduce “pumping losses.” The crankcase cutaways match the cutaways in the cylinder for maximum efficiency.

Optimized, lightweight crankshaft provides fast throttle response.

Short-skirt, forged piston provides excellent reliability and reduces weight too.

The clearance between the cylinder wall and piston have been optimized to increase torque and reduce engine noise and vibration.

Piston oil cooler utilizes a pinpoint nozzle that directs oil to the desired portion of the cylinder and piston, which reduce piston, cylinder and rod temperatures for great durability.

Oil volume in the engine has been optimized to reduce weight and oil drag related power losses.

Lightweight balancer shaft reduces vibration for improved rider comfort and less rider fatigue.

Special crankcase design features an integrated oil tank inside the cases to supply oil to the dry sump lubrication system. This design concentrates mass lower in the frame for optimum handling and lighter weight feeling. There are no exterior oil lines with this design.

The crankcase features a tri-axis design layout for the crank, main and drive axles. This tri-axis design keeps the crankcases more compact while also centralizing mass for better handling. All of the shafts are positioned low in the cases to maintain a low centre of gravity.

Optimized backlash clearances between the drive, driven gears and balancer gears reduce mechanical noise. Backlash is the small “gap or clearance” between meshing gears.

Lightweight balancer shaft reduces vibration for improved rider comfort and less rider fatigue.

5-speed transmission optimizes the engine performance. This 5-speed transmission provides great performance and makes the YZ450F very versatile for MX, Hare Scrambles, Super Moto, Ice Racing and Enduro type applications.

Revised clutch assembly feature a new, more rigid clutch pressure plate to improve partial clutch feeling and help reduce heat build up in the clutch. There is also a change to number of plates to lighten the clutch lever feel / pull.

Quick-access, lightweight magnesium outer clutch cover for fast, easy clutch maintenance. Both the outer clutch cover and crankcase covers feature a mat black finish for added styling

Left and right crankcase cover inspection “plugs” are have been changed from plastic to aluminum for improved durability and ease of use.

Automatic decompression system ensures easy starts in any gear with no manual lever to fuss with.

Convenient, handlebar-mounted hot start lever means easy starting when the engine is hot.

Revised Keihin FCR-MX39 flat-slide carburetor with throttle position sensor (TPS) and leak jet type accelerator pump delivers ultra-precise fuel/air mixing and instant throttle response. The carb settings have been revised for improved power and throttle response.

Washable, dual-stage, foam air filter reduces maintenance costs and provides excellent filtering qualities.

Compact design automatic cam chain tensioner reduces maintenance and mechanical engine noise

Revised CD ignition system delivers ultra-precise spark and optimized timing for faster, stronger engine response. The settings have been revised to accentuate the engine and exhaust improvements.

Ignition coil is integrated into the spark plug cap to reduce weight and complexity.

Compact, lightweight, single core, dual radiators provide outstanding cooling efficiency. Reinforcing bars provide protection in the event of a tip over.

New lightweight titanium header pipe features a revised taper as it exits the engine and a new larger 45mm overall diameter for improved low to mid rpm performance. Titanium heat shields are used.

Optimized header pipe shape not only maximizes power but also allows for hassle-free access to the oil filter.

All new, super short, super compact lightweight aluminum / stainless steel muffler reduces weight, improves handling by centralizing mass and improves styling too. This new design features a ‘tapered punching cone design and long fiber packing to reduce noise and improve the longevity of the packing. This new muffler complies with both CMRC and AMA noise limits.

Trick, works-style clutch lever features a race-spec “barrel adjuster” for on-the-fly adjustability.

New, compact aluminum semi-double-cradle frame features a 5mm shorter cast steering head for improved rigidity and reduced weight. The remainder of the frame uses forged, pipe stock and extruded components. Yamaha has maintained the semi double cradle design to allow for “controlled flex” to optimize suspension action. This frame design provides a lower centre of gravity for a light feel and razor sharp handling, plus less rider fatigue, and excellent stability.

The rigidity balance of the frame at the swingarm pivot area has been optimized for a lighter feeling when turning into a corner

Lightweight removable rear subframe is constructed of square-section, lightweight aluminum pipe. The detachable design allows easy access when servicing rear suspension components.

Lightweight, tapered, aluminum swingarm is produced using “hydro forming”, a special forming method that uses high pressure water to form shapes. The swingarm design provides great overall chassis balance for a light handling feel.

Revised forged aluminum upper triple clamp reduces weight by 17% over last year’s cast version. The reinforcing ribs have also been modified for improved strength and reduced weight. The handlebar holder has also been revised for reduce

New forged aluminum lower triple clamp has a 5mm shorter steering stem to match the new steering head. The shape and rigidity of the lower triple clamp has been revised to improve the overall rigidity balance. It shape is now an “H” shape in the cross section plane.

New, lightweight aluminum adjustable handlebar mounts are taller to accommodate the shorter steering head and steering stem. Their adjustable design allows the handlebars to be moved 10mm rearward if desired.

Pro Taper handlebars are one of the most sought after style of bars and are stock items on Yamaha’s big YZ motocross models. Pro Taper bars provide excellent strength and durability. Foam handlebar pad is included.

Revised 48mm, adjustable, inverted, Kayaba cartridge forks feature a twin-chamber design. The twin chamber design means the damper unit is in a separate structure which prevents aerated fork oil from entering the inner damper assembly and degrading its damping abilities. Since the inner damper is pressurized, it also eliminates bubbles forming in the oil.

The balance between the inner and outer tubes is optimized, while the Kashima coating on the pressure tank and the piston rod reduce friction for smoother suspension performance. The cylinder diameter is 24mm for excellent primary cushioning.

The design of the outer tube below the fork seal has been revised to reduce weight. Low friction oil seals are used to reduce stiction. The compression valve port is lager and the slide clearances to the bushings have been revised to reduce friction and improve damping.

The 48mm inverted KYB fork also features a Transfer Control Valve (TCV). The TCV enhances the damping force of the inner damper from mid stroke to full stroke and improves bottoming characteristics. The benefit of TCV is more precise control throughout the full stroke range. The TCV is located on the upside of the spring and its function is controlled by piston speed, not piston position … hence the term “Speed Sensitive fork”.

“Kashima coating” has been applied to the fork tubes to reduce friction for smoother suspension performance. Front wheel travel is 300mm (11.8″).

Front fork adjustments include: 20-way compression damping and 20-way rebound damping. Optional fork springs are available through Genuine Yamaha parts.

New design “wrap-around” plastic fork protectors provide excellent protection from dirt, mud and stone chips. The “self-supporting” design reduces friction for smoother fork operation. The lower axle brackets have been revised to accommodate the new protectors.

Revised Monocross link rear suspension system features a fully adjustable Kayaba, piggyback shock which provides 313mm (12.3″) of wheel travel and features separate adjusters for high- and low-speed compression damping. Adjustments include: spring preload, 20-way rebound damping, 20-way low-speed compression damping and 2 turns of high speed compression damping.

The shock features a new larger compression valve port for improved damping performance. The piston rod diameter is 18mm and Kashima coating is used in the shock body and sub tank to reduce friction and improve suspension performance during a long moto. The Kayaba shock utilizes a full rebound oil lock system for excellent suspension function and great ride quality.

Lightweight and trick “Beta” titanium shock spring reduces “unsprung weight” which has a dramatic effect on suspension performance. This titanium spring provides outstanding strength, and durability, combined with reduced weight

The rear linkage lever ratio and lower rear pivot shaft and collar diameters have been revised for improved suspension performance and reduced weight. Revised Nissin twin piston caliper is more compact and reduces weight by 27%. It features smaller lightweight aluminum pistons.

Revised master cylinder uses a smaller size piston for reduced weight.

Revised 250mm floating front wave style rotor (disc) reduces weight by 6%. The pins that allow the rotor to float have also been revised to reduce weight.

Revised “shorty style” adjustable front brake lever features an increase the lever travel.

245mm rear disc brake features a new lighter “wave-type” rotor. This new rotor is squeezed by a single piston caliper which features an integrated master cylinder (fluid reservoir is integrated into the top of the master cylinder) for strong stopping power with excellent feel and control. Rear brake pads have been revised for 2008

The rear caliper and the lower portion of the wave rotor are protected by heavy duty plastic protectors.

“Slim line” body components include: front and rear fenders, rad shrouds, side covers /number plates, gas tank and seat. This body design not only provides an aggressive appearance to the YZ450F but also allows for fast, easy rider movements.

Specially designed “Sun Star” rear sprocket increases the contact area between the sprocket and chain rollers, thereby reducing the load on the chain and increasing the service life of both chain and sprocket.

Lightweight, 21″ front and 19″ rear Excel rims provide exceptional durability and help reduce unsprung weight for optimal suspension performance and handling.

New wider 120/80-19 rear tire provides improved traction

Compact engine protector plate offers excellent protection.

“Flat-design” seat features a dual foam design that provides good initial softness / comfort and then increases the firmness as more pressure is applied. The “pebble or “gripper” finish on the top and side surfaces provides excellent rider grip and durability.

Large fuel cap and filler hole ensures easy opening and fast, hassle-free refueling.

New lightweight, extra wide footpegs provide excellent grip and ground clearance. The 2008 pegs are 10mm wider than last year’s version

Cleated, rear brake lever and folding shift lever tip offer superb grip and exceptional durability.

Stainless steel, inner clutch cable provides excellent strength and long life.

Rugged engine and water pump protector plates

Slim 7 liter fuel tank provides great rider mobility.

Lightweight chain guide / support helps reduce chance of chain derailment. Also helps protect rear sprocket damage too.

Heavy duty rubber swingarm protector

SPECIFICATIONS USA – 2008 Yamaha YZ450F:
MSRP* $7,099 (Team Yamaha Blue/White) Available from July 2007
$7,199 (White/Red) Available from July 2007


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

Bore x Stroke 95.0 x 63.4mm

Compression Ratio 12.3:1

Carburetion FCR-MX39 x 1

Ignition CDI

Transmission Constant-mesh 5-speed; multiplate wet clutch

Final Drive Chain Drive


Chassis
Suspension/Front Speed-Sensitive System inverted fork; fully adjustable, 11.8-in travel

Suspension/Rear Fully adjustable single shock; 12.3-in travel

Brakes/Front Hydraulic single disc brake, 250mm

Brakes/Rear Hydraulic single disc brake, 245mm

Tires/Front 80/100-21-51M

Tires/Rear 120/80-19-62M


Dimensions
Length 86.4 in

Width 32.5 in

Height 51.4 in

Seat Height 38.9 in

Wheelbase 58.8 in

Ground Clearance 14.7 in

Dry Weight 219 lb

Fuel Capacity 1.8 gal


Other
Warranty 30 Day (Limited Factory Warranty)

SPECIFICATIONS Canada – 2008 Yamaha YZ450F:
Suggested Retail $8,499 CDN

Engine 4-stroke, liquid-cooled DOHC, 5-valve (titanium), single
Displacement 449 cc
Bore and Stroke 95 x 63.4 mm
Compression Ratio 12.3:1
Maximum Torque 5.4 kg-m (39.1 ft-lb) @ 6,500 rpm
Fuel Delivery Keihin FCR-MX39, flat slide w/ throttle position sensor
Ignition CDI
Transmission 5-speed
Final Drive Chain

Suspension (Front) Adjustable 48 mm inverted fork; 300 mm (11.8″) travel
Suspension (Rear) Fully adjustable link Monocross; 313 mm (12.3″) travel
Brakes (Front) 250 mm floating disc
Brakes (Rear) 245 mm disc
Tires (Front) 80/100-21
Tires (Rear) 120/80-19

Length 2194 mm (86.3″)
Width 825 mm (32.5”)
Height 1,306 mm (51.4″)
Wheelbase 1495 mm (58.9″)
Ground Clearance 374mm (14.7″)
Seat Height 990 mm (39″)
Dry Weight 99.5 kg (218.9 lb)
Fuel Capacity 7 litres (1.6 Imp. gal.)
Colour(s) Yamaha Blue; white

Specifications and features are subject to change