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Russ relocates a berm at Lake Whitney
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In our preview article, we went through many of the technical highlights of Yamaha’s new YZ450F motocrosser. These include larger displacement (the engine displaces 449cc this year), a reduction in weight of 13 pounds (making the bike one pound lighter than Honda’s aluminum-framed CRF450, according to Yamaha), a new frame, new, slimmer ergonomics, and a four-speed transmission. Frankly, we have been salivating at the thought of riding the new YZ450F ever since. We got our chance last week in Texas at the Lake Whitney Motocross track.
MD test rider Russ Somers flew to Texas for a day and one-half of riding the 450F, and a brief back-to-back sampling of last year’s 426F on the Lake Whitney MX track. Russ is a big guy (over six feet tall, and over 200 pounds with riding gear) with lots of racing experience at the pro level. Russ pounded laps in the Texas heat in search of the truth about the new 450F (more laps than any other tester in his group, apparently), and came away very impressed. Here are the details.
Your very first impressions of the 450F are that it is smaller, narrower and much easier to start. With its tiny gas tank (only 1.8 gallons this year), flatter seat and narrower layout, the 450F feels like a smaller bike (a lot like a 250 two-stroke). The ergonomics, in general, provided a very comfortable riding position, with ease of movement on the machine being apparent in the first few laps.
Getting the 450F started before you ride those first few laps highlights another big change. Yamaha developed its own automatic decompression system, and eliminated the “drill” needed to start last year’s 426F. Now, with the bike cold, simply sit on the 450F and kick it through like a two-stroke. The bike starts right up . . . even while in gear!
Russ paid a lot of attention to starting the 450F, both hot and cold. While hot, simply use the handlebar-mounted hot start lever, and the bike starts on the first or second kick. Even bump starting the bike is easy with the automatic decompression system. While the old bike had so much compression it would lock the rear wheel (unless, the decompression lever was pulled), the new bike will bump start easily at three to four miles per hour.
So with better ergonomics and much easier starting, what is the 450F like to ride? Very impressive.
Last year’s 426F was, in many respects, a five-year-old design, but it was still a competitive, effective motocross weapon. Not surprisingly, the new 450F surpasses the 426F in virtually every category, from engine performance to handling.
The 450F motor comes on early and has a very strong mid-range. It continues to pull through the top end, providing an extremely broad powerband. This is one reason why the four-speed transmission works so well. Indeed, the 450F has much more low end power and torque than the 426F, and, basically, more power everywhere through the powerband. While the 426F had a “hit” near the upper rpm range, the 450F is smoother, and very linear in its power delivery. Russ was able to ride almost the entire Lake Whitney motocross track in third gear, and exit most corners with authority without using the clutch. Ridden back-to-back with the 426, the 450 has significantly more low-end and mid-range power, while still pulling at least as hard as the 426 on top. Another great motocross engine from Yamaha.
Overall, the 450F is very easy to ride, and requires very little use of the clutch and the gear shift. Russ was able to put in a lot more laps on the 450F without getting tired when compared with his more typical mount, a 250cc two-stroke.
While the 450 feels dramatically lighter and more maneuverable than the last year’s 426F, don’t expect it to be quite as light and maneuverable feeling as a 250 two-stroke. The handling characteristics featured excellent straight line stability — tracking straight and true over high-speed chop and whoops.
The shock has a nice pleasant feel. It is able to soak up the square edges and keep the rear wheel on the ground. The bike tracks great – almost never swapping. Shock bottoming resistance is good, but heavier and more aggressive riders will need stiffer springs (front and rear).
For Russ’ size and riding ability, he clearly needed stiffer fork springs and more fork compression damping. At first, the 450 wanted to knife or under turn in sharp turns. Once the clickers were turned in three to four clicks, it helped cure this problem.
The forks have a nice progressive feel to them. They handle braking bumps and square edges with minimal shock transferred to the rider’s forearms. On big hits and landings, however, they tended to blow through the travel and bottom with Russ aboard (he ended up with the clickers all the way in.)
The stock tires are Dunlop 739s, a good choice for most Southern California tracks, but the front tire, in particular, seemed poorly suited for the loose stuff at Lake Whitney.
Overall, Yamaha has made a big step forward with the YZ450F, delivering an easy-to-ride machine that could work well for riders of all skill levels, novice to pro.
At a U.S. MSRP of $6,299.00, the 2003 Yamaha YZ450F should be available now at your Yamaha dealer.
