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/127591
(Above) The moto r produces a mellow, no frills -type-o f-power. Thi s year's motor revs much slower, thanks to a heavier flywheel. The frame is purple. (Below) The YZ's rear brakes offer good feel and are not as grabby as past versions. The swingarm is made of a stronger, thinner grade of alloy. (Above) Travel on the Kayaba fork has been shortened, and the result is the best-turning YZ250in years. The front brake is adequate, but nothing more. (Below) The exhaust and transfer ports were reshaped, and the drum-type power valve governor opens quicker. Upshifting under power requires extra attention and a healthy stab at the shifter. Rid ing School, taught by multi-time Supercross and National MX Champion Ricky Johnson. Finally, Yamaha has added to their already-lucrative MX and off-road contingency program, bringing the total to over $5 million. Enough of that, what about the bike? Last year's Yamaha was fast - really fast. What the motor lacked in top end it made up for with a strong basement and what was arguably the strongest and most-violent midrange punch in the class. Well, maybe the graphic artists at Yamaha were a year late with their lightning-bolt des igns. This year's motor was design ed to produce an easier-toride type-of-power than last year 's armjerker. . . Reshaped exhaust and transfer ports, combined with a quicker-opening drum-type power valve governor are designed to produce a stronger low-end hit. The YZ250 was not lacking in that area last year, so Yamaha felt it was critical to transfer the power to the ground more effectively. In an effort to achieve this, designers incorpora ted a 7% increase in the crankshaft's rotational m ass . A di fferen t ign iti on sys tem is claimed to be stronger and sharpen the throttle response as well. Other changes to the motor include steel clutch plates, rather than last year's aluminum versions. The steel p lates, along with a 10% increase in clutch sp ring preload, are des igned to reduce clutch fade under extensive abuse. The transmission gear ratios have also been changed. Second through fourth gears have been spaced closer together, while fifth was geared taller than last year's to provide a higher top speed. Suspension changes were also high on the priority list at the Yamaha factory, and a set of rad ically-red es ig ned Kayaba suspenders grace the new machine. In a time that suspension travel seems to grow greater and greater with each passing year, Yamaha broke that tradition by decreasing their front and rear suspension travel by 10 millimeters. "You don't notice the change in travel while you're riding," explained Yamaha's R&D man Ed Schiedler. "But we've found that the steering and cornering precision impro ves with the shorter travel." In' addition to the decrease in travel, both the shock and fork have been revalved for a better ride. The shock receded a four-millimeter-larger compression damping valve, upping its size to 18mm, and the fork boasts a pair of stiffer springs that help resist bottoming. The YZ's frame sports nearly exactly the same geometry as last year, but this year's purple-pa inted version is beefedup with stronger gusseting near the headset area. YZs have always be.en known for their stable chassis, 'and for being reluctant to hug the inside line in comers. In order to improve cornering in tight situations, the steering locks allow 3mm more turning radius. Also, the rake of the fork is steeper, though only by an infinites imal amount. Th e sea ting position is sligh tly different, with the pegs being raised by five millim eters. The sw ingarm is made of a stronger alloy that allowed for the use of a thinner cast portion and resulted in a subsequent reduction in weight. As an option, Yamaha offers a titanium subframe that weighs 1.4 pounds less than the steel vers ion and costs $249.95. Rounding out the "over 50" changes and improvements are a simplified onep iece rigid handl ebar crown that replaces last year 's rubber-mounted versions, a flatter, taller seat, redesigned brake rotors and brake pads, and a reshaped rear brake pedal. Despite all of the lightened and simplified parts, the claimed dry weight of the YZ250 remained the same, 220 pounds. l:N While Cycle News believes theforegoing test reliable, it is the opinion of the reviewers only and should not be relied upon in determining the performance or safety of thevehiclets). The reader should make his or her own investigation 17