Cycle News - Archive Issues - 2000's

2001 Yamaha WR250F Apparently Yamaha sensed this, for it sweetened the proposition of trying out its newest little thumper by arranging for its press introduction to occur at the South Carolina home of Team Yamaha's six-time AMA National Enduro Champion Randy Hawkins, and inviting us along. To fully appreciate the sweetness of this function, you must first realize that Hawkins' property contains an ISDEworthy grass track (with buffalo and llamas serving as unimpressed spectators), a red-clay motocross circuit, and a five-mile terrain-test loop through some of the most dense woods this side of a Christmas-tree farm. In addition, there's an indoor basketball court in Hawkins' house, along with a complete race shop just up the hill. Not only that, but the lovely Kathy Hawkins even acquiesced to cook for her loud, dirt-covered visitors and allow them to watch Speedvision's Dakar Rally coverage and ESPN's MotoWorld (guest-starring her husband) on her big-screen television. Clearly, this was a deal too good to pass up, especially when Yamaha P.R. coordinator Terry Beal ordered up ideal weather conditions and invited along Yamaha GNCC star Barry Hawk to keep Hawkins compa- By CHRIS JONNUM PHOTOS BY JOE BONNELLO/YAMAHA r;;}ity the poor Yamaha dirt-bike Lj--" test rider. Oh, sure, it seems like a cushy enough assignment, taking a paycheck and enjoying a comfortable benefits package, all for performing an activity that many willingly pay good money to partake in - namely, spending the day in the saddle of a nice dirt bike. But seven nice dirt bikes is another proposition altogether, and we've got to guess that after painstakingly evaluating and fine-tuning the YZ80, YZ125, YZ250, YZ250F, YZ426F and WR426F, the beleaguered Yamaha testing department cried "uncle" when engineers rolled out yet another new competition model - the WR250F four-stroke off-road bike. Implausible as it seems, it is possible to have too much of a good thing, even when that thing is dirt-bike riding. Trust us we're beginning to feel a bit overwhelmed ourselves from our own attempts to evaluate the never-ending stream of new motorcycles (many of them blue) that empties at our office door (we still haven't had time to write our test of the WR426F). 16 FEBRAURY 7.2001 • cue • e n e _ s ny when he left the slow journalists behind on the trail. WAY RADICAL If you have absorbed any part of the recent flood of press on the YZ250F, then you're already fairly familiar with most aspects of the WR250F, though Yamaha did make several important changes to the motocrosser in the interest of offroad worthiness (see "The Formula" sidebar). With the YZ250F, Yamaha wanted not a low-rpm plonker, but a thumper that screamed like a 125cc twostroke, and despite its intended applicatio!,!, the WR is no different. Like the motocrosser, it's got titanium valves (three intake, two exhaust), a light, short-skirted piston, a shortstroke motor, a ceramic compositecoated cylinder bore and a low-friction crankshaft. The feathery valves allow for lighter-weight valve springs, and the entire combination makes for a motor with minimum friction and reciprocating mass - in other words, a motor that can rev to the moon (Yamaha claims over 13,000 rpm). Though it's "just" a little 250, Yamaha saw fit to include a counter- balancer on the WR, and it resides at the front of the motor - just in front of and slightly above the crankshaft. Although including such a feature does make for an increase in the reciprocating weight Yamaha was trying so hard to minimize, engineers felt that since the balancer reduces vibration, other parts of the motorcycle can subsequently be designed lighter than would otherwise be possible. (We've heard that Yamaha of Troy's race bikes have the balancer removed, but parts are replaced often enough on those machines that vibration fatigue isn't a problem.) The only problem with designing a motor with such specific tolerances is just that specificity. In other words, you can't just take a 426F bottom end and throw on a smaller jug. (While the 250F's motor is shared between the quarter-liter YZ and WR four-strokes, it shares very few parts with its bigbore sibling.) The advantage, however, is that you can make a bike as light as possible, which is why there's a substantial weight difference between the two WRs, while KTM's 400 and 520 EXCs share identical weights. (The 250F's frame is also different from that of the 426F.)

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