Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/127790
NEW BIKES. 1997 Honda CR MXers 9 (Left) Honda basically took conventional frame philosophy and set It aside In designing the first aluminum, dual-box-sectlon, twin-spar frame to be used In a production MXer. Honda learned a lot about aluminum, twin-spar frame technology from the company's road racing department, such as with the CBR900RR. By Kit Palmer onda is leading the way into a new era of motocross technology with the introduction of the very first production, aluminum-framed MXer to feature dual-box-section twin spars, box-section downtubes and compact forged pivot plates. The 1997 Honda CR250R is the recipient of this new technology, and is scheduled to appear on showroom floors by mid-September. The new frame, which borrows much of this new aluminum, twin-spar technology from Honda's road racing department, is said to be stronger and four pounds lighter than the previous steel frame. The advantages of this new frame design are many, according to Honda. The frame is not only lighter and stronger, thus increasing lateral and torsional rigidity, but also permits easier carburetor and engine maintenance and allows the main volume of the 2.D-gallon fuel tank to sit lower and farther back in the frame for greater contribution to mass centralization. Another advantage with the new frame design is that a new, single-unit radiator can be used instead of two separate units; Honda claims that the new one-piece radiator increases cooling capacity by 150 percent. The overall frame geometry is similar to that of the 1993 CR250's frame, the frame that Jeremy McGrath has used in his race bike ever since. The new frame offer 28 degrees, two minutes of rake; 116.5mm trail, and 24mm of steering offset. H 14 (Right) The new frame is claimed to be four pounds lighter, and stronger, than the previous steel, conventional frame. The geometry Is nearly identical to the 1993 CR250's frame, the frame that Jeremy McGrath uses In his race bike today. Honda tested a variety of forks on the twin-spar frame, including conventional forks, but settled on a 47mm, inverted, Showa twin-chamber, cartridge fork, that includes rebound and compression damping adjustability. Honda claims the new fork offers more consistent damping, longer intervals between service and a better bottoming system. Strangely, the rebound and damping adjusters have traded places the rebound clicker is now on the bot- tom of the fork leg and the compression on the top. The fork now comes with a softer .40 spring. The rear suspension received a major overhaul as well. First of all, there's an all-new, tapered, box-section aluminum swingarm that Honda claims is lighter and increases ground clearance. When it came to testing new shock linkages, Honda started out with the same ratio McGrath uses but found what's good for him just wouldn't be so good for the general masses and compromised on a ratio somewhere between McGrath's liking and the '96 ratio .. Honda testers couldn't bottom last year's ('96) rear suspension but can on the '97. You know the old saying that a properly tuned-in suspension should bottom out at least one time a lap around any given track. The Showa shock still offers "millionway" high- and low-speed compression damping adjustments, as well as