A little Kiwi birdy from New Zealand where they test these machines just told me:


The most hi performance 4 stroke dirt bike engine ever in production is now
nestled in a quad chassis.............. the YZF 400/426/450 series. These
things eat KTM 520's for breakfast and are as reliable as a rock unlike
Hondas fragile CRF 450 time bombs.............

The new 450 is a rocket ship in the YZ and WR dirtbikes, these things are
both high rev and torque monsters, if fact the new 450 configuration is
described as brutal in the bikes and I will predict now that it will
make the LTZ look like a toy and will expose the Predator weakness, lack of
torque !

As for the front shocks they are both compression and rebound adjustable,
full rebuildable with alloy bodies and hey the ressies are standard.

I full expect Raptor brakes, hubs etc. The vast majority of it is new new new.

The rear suspension linkage is total new and very much like the Suzuki with
a short vertical shock. The plastic and layout is all new, ergo's way
differnt to the Raptor, alot lower in the tank / nose.

 

Anyone have any idea what kind of HP numbers these will put out??

 

No way would Yamaha release a 450 that would outrun their Raptor, I look for it to be in between the Z400 and the Raptor.

 

Width? Length? Weight?

 

um... those aren't really tech specs...

 

MSRP
$6,899* Available from June 2003

Engine
Type 439cc, 4-Stroke Single, Liquid Cooled w/ Fan, Titanium 5-Valve DOHC
Bore x Stroke 95mm x 62mm
Compression Ratio 11.9:1
Carburetion Keihin 39mm FCR w/ Throttle Position Sensor
Ignition DC - CDI
Starting System Electric
Transmission 5-Speed Manual Clutch
Drive Train 2WD; Sealed O-Ring Chain
Chassis
Suspension/Front Independent Double Wishbone, 9.1” w/ Compression and Threaded Preload Adjustment
Suspension/Rear Aluminum Swing Arm, 10.1” w/ Rebound, Compression and Threaded Preload Adjustment
Brakes/Front Dual Hydraulic Disc, Twin Piston
Brakes/Rear Hydraulic Disc
Tires/Front AT21 x 7-10 Radial
Tires/Rear AT20 x 10-9 Radial
Dimensions
L x W x H 72.4” x 46.1” x 42.9”
Seat Height 31.5”
Wheelbase 50.4”
Ground Clearance 4.4”
Fuel Capacity 2.6 Gallons
Dry Weight 350 Lbs.
Other
Lighting Dual 30W Krypton Multi-reflector Headlights & 21/5W Brake light
Colors Team Yamaha Blue/White; White/Red
Warranty 6 Month (Limited Factory Warranty)

Liquid-cooled, 439cc, 5-valve, DOHC, 4-stroke with titanium valves features 95mm bore and 62mm stroke delivering, broad torque curve (for instant hook-up) with high over-rev capacity and crisp, linear throttle response.

Reliable, push-button electric start in any gear adds extra convenience.

High performance 39mm Keihin FCR flat-slide carburetor with throttle position sensor (TPS) delivers ultra-precise fuel/air mixing and instant throttle response.

Dry sump engine carries oil in an aluminum tank directly in front of the engine for excellent cooling and optimal protection from rocks or mud.

Digital CD ignition system delivers ultra-precise spark and 3D timing for faster, stronger engine response during hard acceleration.

Lightweight crankshaft keeps inertial mass to a minimum for faster-revving low-rpm response.

Piston features short skirt and small pin boss diameter to help reduce weight.

Lightweight titanium valves (first ever on an ATV) and load-reduced springs are super light, minimizing reciprocating mass for fast-revving, hard-hitting power delivery across the RPM range.

High-performance stainless steel exhaust header (and heatshield) is mated to a USFS-approved spark arrestor which looks trick and resists corrosion.

The large-capacity radiator is optimally mounted in the frame to keep the center of gravity low but away from mud or rock damage and provides outstanding cooling efficiency.

Additional weight-saving engine features include: magnesium cylinder head cover & right side crankcase cover; small-design cam chain tensioner and oil pump; aluminum oil hose; and light CDI ignition unit.

Ignition coil is integrated into the spark plug cap, the first time ever used on an ATV, and is extremely light and compact.

Smooth-shifting YZ-spec ratchet-type manual 5-speed transmission delivers engine’s potent powerband to the ground with maximum efficiency and hook-up.

Heavy-duty manual clutch features extra-thick plates specifically designed for the YFZ450.

Large capacity airbox features no-tool access to the oiled dual foam filter for easy maintenance.

Trick, works-style clutch lever features oversize barrel adjuster for easy, no tool adjustability of lever/cable play.


Chassis/Suspension:

State-of-the-art high-tensile steel chassis utilizes the most advanced suspension technology ever fitted to an ATV for pure-competition-spec performance right off the showroom floor.

Independent aluminum upper A-arm front suspension features fully adjustable competition-spec Kayaba piggyback shocks with 9.1" of travel and separate adjusters for preload, rebound and compression damping.


Rear suspension system is a YZ linkage-type that features fully adjustable Showa shock with 10.1" of travel and separate adjusters for preload, rebound and compression damping.

Ultra-rigid cast aluminum swingarm reduces weight and ensures optimal, flex-free suspension action.

Numerous aluminum components—including the swingarm, upper A-arms, oil tank and wheels —help keep overall dry weight down to a paltry 350 pounds, making this the lightest weight 4-stroke sport ATV ever.

Lightweight front and rear master cylinders, combined with twin 160mm front discs with twin-piston calipers and single 200mm rear disc, deliver incredible stopping power with progressive control and feel.

Ultra-compact, race-bred chassis design creates a short 50.4" wheelbase and low center of gravity to create a super-tight turning radius.

Removable aluminum die-cast rear subframe removes easily for maintenance.

Long, low and narrow YZ-style seat is only 31.5" high which enhances the low center of gravity for quick, balanced steering and optimal rider movement.

High-performance 21 x 7R-10 front and 20 x 10R-9 rear Dunlop radials, designed specifically for the YFZ450, deliver superb, class-leading traction.

Lightweight aluminum wheels help enhance suspension performance by reducing unsprung weight.


Additional Features:

Aggressive YZ-inspired styling of front cowl, tank, fenders and seat establishes this machine’s pure competition purpose.

Dual 30-watt multi-reflector halogen headlights set back in the front cowl add the perfect menacing appearance. Taillight has an incorporated brake light for added convenience.

Rugged 45mm-wide serrated footrests provide excellent grip and rider comfort.

Large-capacity, 2.6 gallon fuel tank ensures excellent range.

Easy-to-use, toggle link-type handlebar-mounted parking brake can be set with one hand.
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Who has had their butt planted on one? Should be a fun summer.

 

Eat the KTM 520's for breakfast? You been smokin' crack again haven't you. Try a straight line drag, yzf450 against the ktm520 bike, you'll see that the 520 will eat it up. That's why they don't race in the same class. I imagine they did the same thing to the quad that they did to the wr, in that they've blocked up the airbox and restricted the exhaust. If they've done that, and put in the lower compression piston, I bet they've changed the cam timing. I would bet that they are putting out maybe 40hp. Gotta leave something for the aftermarket to do, right?

BTW - I own a 03 crf450 time bomb, and when my friend and I (he owns an 03 yzf450) get on the wide open fire roads, I roll on the power and go by him. We both put yosh exhaust on our bikes, and had them jetted on the dyno. My bike put out 56 rwhp, his put out 51 rwhp. We bought the bikes a week a part, ride 'em hard, and neither bike has had any problems. I have to admit, the mid-range hit on his bike is nasty, but the power band doesn't pull as hard/long as mine, and if I go into 5th gear, I can drink 3 beers and take a leak before he catches up.

 

I said the same thing....but Yamaha states the 450 has the lowest power too weight ratio available.

 

Comon guys, let it hit the street before you start talking crap about it. Personnaly, I think it's going to put the Raptor to shame. Once the aftermarket stuff starts comming out and it gets geared, piped and jetted it may be THE bike to beat. But what do I know. It may turn out to be a piece of crap wana-be. Guess we'll have to wait and see.