Coming into the world of ATV racing, the Yamaha engineers already had a good chance of taking over the market. From the first YFZ450 to the latest, they have proven a point and let the world know that greatness is at hand. Tucked in the hills of Union South Carolina there would be a mystical creature named “Big Buck” and little did this evasive horned mammal know but there in the same land this day was the fierce blue competitor called Yamaha.

Getting to test the new 2010 Yamaha YFZ450X model at “Big Buck”, the home of the fourth stop of the Grand National Cross Country racing circuit, would be exciting for most anyone but knowing that this machine was specifically built to perform in this terrain, made it even sweeter.

As the years have passed since the release of the YFZ450 there has been speculation of further adapting this machine to make it more suitable for tight woods and various climates or altitudes straight out of the box. The evolution of the YFZ450 would change once again in the fall of last year to introduce the YFZ450R. The R however was really better for Motocross-style racing.

R-Rated versus X-Rated

Starting with the same great engine in its R-rated sibling, the “X” model will get a remapped fuel-delivery, bringing the engine under control for tight woods and XC racing in general. This engine has the five Titanium valve head and dual-overhead cams that make explosive yet controllable bottom- and mid-range power to propel the beast into the woods. Being a single-cylinder and liquid-cooled, this four-stroke brings a knockout punch to the competition without sacrificing durability. The fuel is fed to the throat of this engine by a 42mm Mikuni throttle body and it is atomized into the cylinder by the Denso 12 hole injector. What does this mean for the rider? Extreme pucker-factor has been achieved right off the showroom floor!

Where are the major differences in this machine, besides the fuel mapping, compared to the YFZ450R?

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The overall size would be a most noticeable difference at first glance. The width of the front as well as the rear gives this machine a compact figure. Shortening the front arms to 395.2 and cutting the rear axle by 50mm in length gives this YFZ450X the ability to squeeze into the tightest woods courses. The suspension has had a major overhaul to improve its trail-ability as well. Getting the width down was a concern of the Yamaha engineers and this would be the first of many here in the swings of the YFZ450X.

Taking the same width of the original YFZ450, 46.1 inches, was a no brainier but how could they transform the handling of the YFZ450R model to work right in the woods by doing this? Starting with the front suspension on the “X” model we find 36mm shorter KYB shocks. These shocks will feature Kashima coating and increased oil capacity that reduces shock fade thus increasing durability. The awesome High/Low compression and rebound adjustability of the shocks on the YFZ450R has been transferred to this YFZ450X along with threaded preload adjustability as well.

In combination with the narrower width, shorter yet larger diameter shocks and the steering geometry the YFZ450X handling is built for wooded trail competition. The caster has been changed by one degree from 5 to 4 and Yamaha claims this will be noticed in the half to full lock turn of the bars by reducing the effort in tight corners. This gives a lighter feel to the steering, reduces fatigue and allows the rider to ride aggressively longer.

The frame on the new YFZ450X is exactly the same as the YFZ450R, and unlike the original YFZ450, the front suspension low side pivot points are moved inward and are 16mm closer together. The upper pivot placement has also been moved 59mm closer. Changing the way the A-arms arch is yet another feature that will be taken from the YFZ450R. The reverse angle on the bottom arms will give up more ground and obstacle clearance to the rider’s machine.

There are many features that have been adapted from the YFZ450R, and with that machines success why not? The controls for this machine are also transformed into the “X” model and as you will hear later in this article I love the ability to adapt this machine to most any riders particular size and seated position.

The bars first off are quality PRO-TAPER brand flexible bars and these will also reduce fatigue from the typical steel non-flexible predecessors. The bars are adjustable with four positions actually being found in the eccentric clamps and the location of the mounting of the clamps themselves. Being able to move the bars and not change the feel of the steering is a plus for larger riders.

This machine was not large/tall rider friendly when it came to life as the YFZ450, but with much consideration from the factory I can now say it is.

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The Ride

This brings us to the ride. Big Buck is known for its severely tight trees and since the rain had not let up in the days prior to our ride, we knew the mud was waiting.

The first trip around the 10-mile loop would let me know that the bars needed to be moved in order for me to steer the beast. The Yamaha mechanics got on it and in just a few minutes I had 10mm more room between the controls and myself. The bars were also rolled up a notch and after the adjustments we set back out to check the changes. This gave me needed steering room, as it kept the bars out of my knees and side when crunching the tighter corners.

The brake lever on the bars then would be a little far off but that was easily adjusted to be a bit closer for my reach as well. I love these little things that make the ride tailored to my size and riding preferences.

The power of this machine is very explosive on the bottom, yet truly linear and smooth. There is also plenty of power for the average rider and racer through the midrange as well. Launching the front end up and over obstacles was as easy as just blipping the throttle. I was surprised how the engine responded to my demands.

After just a few miles in the woods I found myself ripping into second and third for most of the day. The engine power, the way it is mapped and geared for the woods allowed me to lug this thing anywhere I wanted. Running a gear tall was not a problem for me. The thumb throttle just needed a bit of pressure and the engine would ramp up and tear away at the ground. I did notice some stumbling in the throttle until the unit fully warmed up.

The brakes could stop a freight train and remained very consistent throughout our ride.

The saddle on this YFZ450 is very comfortable and moving around on the machine is effortless, due to the thin central seat. Getting way back on the quad I found plenty of plush seating yet it did not get in my way as I moved around and from side to side.

With the super-wide aggressive foot pegs at 65mm wide there was no problem getting a grip even in the muddy conditions. In the event you got to the edge of the peg there was a tall kick up at the end to catch your foot.

My only initial concern with this machine was the stock set-up of the shocks. Because I am a larger rider, I know the average rider click and spring wasn’t going to fit. I'm sure that with a little longer seat time and adjustments I could dial these shocks in a lot more for my weight. The days of tossing the stock shocks out are over for the average racer. Re-valving these would be simple and I'm sure there will be stiffer springs available soon.

Overall this machine has tons of potential and after a few hours of riding the new YZF450X, I was scared it would take 10 morticians to get the smile off my face. I cannot wait to get this beast to my local riding area and give it a long-term test. Go out and test it for yourself, because nine championships for this company proves they are doing something right!

RS