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2004 Honda CRF250R Development
Honda's 2002 CRF450R turned out to be an instant hit. In short order this new magnum-sized thumper won its first Supercross, an accomplishment that established its credentials as a world- class race bike. The CRF450R's reputation only continues to grow as the big four-stroke continues its winning ways in National motocross competition.
Just as significantly, the CRF450R soon made a huge impact beyond the motocross arena, because of the bike's broad, deep capabilities. From flat-track racing to scrambles, Supermoto, off-road events and more, a crowd of top-rank professionals have claimed race victories aboard Honda's big-bore four-stroke. What's more, the big CRF has delighted legions of weekend recreational riders with its remarkable breadth of abilities.
This grand-slam success ensured the arrival of a second, smaller four-stroke racer, one that perhaps will prove even more revolutionary because it dispels a few long-standing myths in the two-stroke vs. four-stroke debate. Imagine a four-stroke motocross racer that is actually lighter than its two-stroke counterpart--impossible, right?
With the 2004 CRF250R, the impossible becomes possible. Weighing 206 pounds dry, this new four-stroke 250 scales out a feathery nine pounds lighter than the new Honda CR250R two-stroke, a machine that emerged as an overpowering force in the toughest Supercross and motocross races in the world. And that's just the beginning of the CRF250R's story.
As with many other production Hondas, the CRF250R was developed at the company's Asaka R&D Center. While the CRF450R and CRF250R share the same basic SOHC Unicam engine configuration and both utilize an aluminum frame, the 250 boasts unique technological advances. More than merely a smaller version of the 450, the 2004 CRF250R is an all-new machine, in some ways a generation ahead of the 450. The 250 promises to not just be a front-running motocross mount, but also just as well-rounded--and successful--as its big brother.
Ongoing steps in an evolutionary progression
According to CRF250R project leader Yasuhiro Nakayama, "The final CRF250R is quite different from the CRF450R and the initial 250 prototype we built. Obviously, the 250 is smaller than the 450, but it also has a significantly higher rev ceiling. We wanted the 250 to have strong acceleration and good punch coming out of the corners, but we also knew that giving the engine too much punch would lead to jerkiness that could spoil the good traction that is one of the inherent benefits of four-stroke power. It could also make it harder to effectively use the machine's engine braking characteristics. We also wanted the CRF250R to appeal to a broad spectrum of riders, and that meant paying attention to a number of new elements that hadn't been required with the CRF450R. Striking the best balance between all these elements wasn't easy."
As would be expected with a high-performance machine of smaller displacement, the CRF250R engine revs much higher than the 450 engine. While the big 450 approaches the 11,000-plus-rpm level, the 250 is designed for engine speeds in excess of 13,000 rpm-stratospheric levels for a single-cylinder engine. So the CRF250R engine design had to incorporate greater rigidity in the cylinder head and valve train areas to accommodate such ultra-high engine speeds.
To those familiar with modern Honda motocross machines, aluminum frames now seem commonplace. But the development of an all- new 250 four-stroke racer served as the perfect opportunity to create a re-engineered fourth-generation aluminum frame mated specifically to this new quarter-liter machine. The very size and nature of the smaller four-stroke engine opened the door to development of an all-new frame that draws on the experience Honda has gained from both its four-stroke and two-stroke racers. Because the CRF250R's engine is more compact and lighter than the 450's, the 250's frame proportions could be redesigned correspondingly smaller. In fact, compared to the CR250R's chassis, the four-stroke's weighs decidely less. So the CRF250R evolved into the next step forward in chassis design compared to both the CRF450R and the two-stroke CR250R.
Brilliant innovation. Hard-won experience. Excellence in engineering. A design that springboards off the much-acclaimed CRF450R. Sounds like the perfect formula for success with the newest Honda motocrosser, the 2004 CRF250R.