2004 YAMAHA YFZ 450

While some ATV manufacturers have avoided introducing sport or high performance quads over the last 15 years, Yamaha has never retreated one inch. They have kept a strong presence in the sport ATV ranks with their Banshee, Warrior and Blaster for well over a decade now and continue to offer these machines to a throng of ATV purists worldwide.


For the 2004 model season, Yamaha has introduced an all new model, designated the YFZ450, to their extensive sport and high performance ATV lineup. This revolutionary quad is set to change the entire nature of the high performance market.

While this is not the first ATV to be aimed at the racing market, the YFZ 450 is the first Japanese-produced quad that is targeted directly towards the full-on racer. It is the most serious, affordable and anticipated machine to arrive on dealers’ showroom floors since the Honda 250R.



Yamaha has upped the ante in the performance ranks by putting their high tech, YZF450 engine inside an all new competition-styled ATV chassis. They added state-of-the-art suspension, a pushbutton electric starter, and then incorporated numerous aluminum components to make it the lightest, fastest and best handling performance machine ever offered to the general public.


The motor itself is derived from Yamaha’s popular YZ motocross bike. It uses a liquid-cooled, five-valve, Double Overhead Cam (DOHC) four-stroke engine with titanium valves. The standard bore on the new race quad is 95mm with a 62mm stroke. That gives it a displacement of 439cc instead of 450cc.


Why a 439cc engine instead of a full 450? Yamaha wanted racers to be able to take this machine out and compete with it in the ATVA Nationals. Rather than make racers have to invest in a sleeve-down kit for the motor, they adhered to the class 440cc displacement limit. That is how serious they are about the intended use of this machine.

Unlike a lot of fence-sitting ATV manufacturers, who seem to be driven more by their corporate fear of attorneys than by a desire to race or improve the product, Yamaha makes no qualms about the intended audience for this machine. They want racers to flock to it. They want riders who want the best possible machine for the track, not a compromise trail quad that would cost a fortune to turn into a racer.

Simply put, this is a production race quad. It was built by a company that thrives on competition. Possibly, a large percentage of the buyers might not even end up racing it, but Yamaha wanted to be sure that those that do will not be disappointed. Or go broke trying to.



To do that, that have carefully put together a package that in stock trim is as good as many fully customized (and highly expensive) racers already out there. The YFZ450 uses a dry sump engine which carries its oil in an aluminum tank mounted directly in front of the engine for increased cooling effect.


It uses a lightweight crankshaft for better throttle response and quicker revving and the carburetor is the same as that found on the exotic YZF 450 dirt bikes, a 39mm Keihin FCR flat-slide carb. This was another nod to the competition-minded rider, as this is an extremely expensive carburetor. The bean counters could have told the engineers to settle for a less expensive “CV” style carb on the unit. But the engineers and testers insisted on the costlier and better performing FCR carb. Score one for the tech gurus.

There are other high tech items on the YFZ450, such as the integrated spark plug ignition cap, which is a first for an ATV. The lightweight titanium valves on the five-valve head are also a first in the ATV world. To make sure the gearbox and clutch were up to speed, the internals on the five-speed, manual clutch gearbox and clutch have been beefed up to withstand the added stress a four

wheeler places on these components.


To our relief, the engineers have finally seen the light and incorporated a brand new, massive airbox with a single stage foam air filter. It also has a built-in removable air box lid. You don’t even need any tools to get to the filter or remove the lid, as it snaps in place.


The high tensile steel chassis is designed to offer a low center of gravity but also uses lightweight aluminum components such as the removable rear subframe. A forged, one-piece cast aluminum swingarm is a virtual work of art. The dual A-arm front suspension uses gull-wing style lower steel A-arm mounts with an upper aluminum arm. Kayaba piggyback reservoir shocks are mounted up front and feature rebound, compression and spring pre-load adjustments and 9.1 inches of travel.


On the back end, the single shock swingarm comes with a YZ-style linkage with a Showa shock with pre-load, compression and rebound adjustments and 10.1 inches of travel. The wheelbase is a compact 50.4 inches with a width of 46.5 inches and length of 72.4 inches. The machine has a low seat height of only 31.5 inches that helps contribute to its extremely low center of gravity. The seat itself is on the long side and extremely flat.

This helps when making weight transitions from front to back.


All new Dunlop radials were built for the YFZ450 as well. The fronts appear to be close cousins to the Raptor radials but are a slightly different design. The rear radials are completely new and have a knobby pattern much like that of the popular Ohtsu radials.

The fuel tank holds only 2.6 gallons and Yamaha recommends using only high test gasoline in this engine, not regular. Dual twin piston hydraulic disc brakes are mounted up front with a single caliper hydraulic disc located in the rear.


Dual 30-watt halogen headlights are mounted up front and are easily removed to save a few pounds for the racing purists. Even the footpegs have been “racerized” with serrated turn-ups at the ends to help keep the rider’s feet glued to the pegs. The YFZ 450 will also have an extensive line of performance products available for it at its launch, from Yamaha’s in-house accessory line. The Genuine Yamaha Technology-Racing (GYT-R) products include nerfs, mufflers, jetting kits, and billet parts. There is even an accessory kickstarter kit for the machine, for racers who want to remove the stock electric starter and battery to save more weight.



To get an idea of how this all new race-inspired YFZ450 performs, we headed out to LACR, a local motocross facility located near Palmdale, California. The Palmdale track features a jump-laden, sandy loam course with lots of tabletop jumps, doubles and lush turns with just enough fast sweepers to allow us to push the machine to its uppermost limits.


To better communicate to you what it feels like to ride this machine, here is what a typical lap around the track was like aboard the new YFZ450.

First, you fire up the motor by hitting the starter button, located on the left side of the handlebars. This cranks the machine up immediately. It soon reaches operating temperature and you’re ready to snick it into first gear and ease out on the clutch.

The clutch itself is very smooth and easy to use; it has an almost hydraulic-like feel to it. You ease it out and nail the throttle and get a perfect roost off the rear Dunlap radial knobs. Instead of the front end reaching for the sky in a power wheelie, it simply accelerates forward, not up.


As you drive off the start, there is no problem simply banging through the gears without backing off the throttle with each shift. This allows you to maximize the YFZ450’s solid and strong mid-range muscle. One thing, though; you can hardly hear the motor as you’re riding. It is so quiet (82 dB) that you hear the suspension and tire noise instead of the sound coming out of the back of the exhaust. It feels like there is a giant cork in the muffler and if the engine ever dislodges it look out!


First gear is a bit on the tall side but not objectionably so. The gear ratios feel close and are well tuned to the machine’s performance. Tire hookup is phenomenal. Weight bias is first rate and certainly aids the way the machine transfers traction to the back end under hard acceleration.


We felt the acceleration on the stock YFZ450 was as good as a lot of built-up Z-400s we’ve ridden. Again, this is with the machine in its “corked” or bottled up state (see sidebar on the “uncorked” YFZ we rode later). By simply removing the stock air box lid, adding an accessory muffler, and rejetting, the difference in power output is amazing!



As you approach the first turn, it’s simply a matter of transferring your weight to the inside of the machine and it automatically arches out into a perfect full throttle slide, almost like it was on rails. The YFZ450 sits very low and it is extremely easy to keep the throttle on and nail it and power your way through turns.

The front and rear disc brakes are easy and comfortable to use and are even adjustable for different reach hands. They have outstanding braking power. These are perhaps the best brakes ever offered on a production quad. They’re smooth, controllable and very powerful.


Scrubbing off speed easily, you tap the brakes before heading into a series of sharp turns with several long straights connecting them. Since the YFZ’s steering is ultra predictable  and very precise, it can hug the inside line or rail the outside berm. This gives you lots of choices as you approach the end of the next straight-away. You pick the inside line and square up the machine and glide through the apex. Wow, the quad stays glued to your line and accelerates seamlessly into the next turn.

The YFZ has a stable and secure feel to it when sliding. It tracks straight and true. The ergonomics are so good that even our larger test riders didn’t have a problem with their knees knocking on the front plastic as they slid forward and hung off the quad in the corners. Riders over 6’2″ might feel a bit cramped on the machine, since it has such a low c.g. and seat height. But even the big guys thought the ergonomics and handling were first rate. The flat seat makes moving around quick and easy.




We were now headed for the first tabletop jump, which is followed by a short straight and another bigger tabletop jump. We sailed off the first jump, a bit concerned that maybe we had hit it a bit too fast.


No problem, though; the YFZ’s suspension is simply incredible. It soaks up the worst hits, with no hint of bottoming or loss of control. The faster you ride, the better it works. We landed and didn’t suffer any ill consequences for our overly enthusiastic leap. Back on the throttle again, we hit the second jump even faster, sailing further and landing again under full control. After that, we were firm believers in this quad’s suspension.


The YFZ450 has to have the most race-ready production suspension that has ever come bolted on a Japanese quad. We have ridden with fully setup custom shocks that don’t work as well as these units. The dual Kayaba front shocks and single Showa rear shock perform on a whole new level. This is not a machine that you will need to shell out an extra few grand to upgrade the suspension for racing. They are that good, stock!

Fast approaching, though, was one of LACR’s massive big air doubles that require an unflinching committement from rider and machine. With our confidence boosted by our experience overjumping the earlier tabletop, we nailed the throttle and let fly. The YFZ 450 launched off the jump with NASA-like precision. This is an amazing machine in the air. With its light overall weight and low c.g. it is one of the easiest quads to flick around in the air that we’ve ever ridden.


Since the YFZ motor has oodles of torque, we soon found that the hot setup was to let the machine run a gear high in the corners. We would then use that massive torque to run up to the jumps and do major air launchs off them. The YFZ450 has very stable flight manners and you feel very confident hitting jumps at full throttle.



On some of the rougher sections of the track we got a chance to see how well the fully adjustable suspension holds up to repeated poundings. We found that the shocks offer smooth, damping action and keep the wheels hooked up and getting forward momentum, even over very choppy ground. While the phrase “anti-squat” might be more of an advertising slogan than pure fact, the YFZ 450 does remain fairly stable, with no tendency to “squat” in the rough. There is no see-sawing, bucking or swapping whatsoever.


Since the Showa and Kayaba shocks have piggyback reservoirs, they seem to hold up well to repeated poundings without heat fade affecting the performance. With their adjustable compression, rebound and preload settings, they can be adjusted to suit almost any combination of terrain, or rider skill level.

That isn’t to say the YFZ offers a plush, pillow-like ride. For riders who want to just putt around, off the gas, the ride can be a bit stiff and even jarring. The Raptor offers a far plusher ride for the casual trail enthusiast. But once the speeds increase and the driver starts to get aggressive, the YFZ 450 suspension can’t be touched.



The new YFZ 450 is by far the best production quad we’ve yet seen come down the ATV product pipeline. It is the lightest (at 350 pounds dry), the best handling, and especially once you “uncork” it, the fastest-accelerating high-performance quad we have yet ridden. There is little doubt that this will be the most popular machine to hit the race tracks of this country since the legendary 250R.

Is the YFZ450 the new king of high performance racers? We think so. If there are any serious challengers out there, they had better start brushing up on their homework. Yamaha certainly did.


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