Suzuki Rm250 Vs. Yamaha Yz250
Suzuki RM250 vs. Yamaha YZ250
Two-strokes aren’t dead yet!
BRIAN CATTERSON
IF FOUR-STROKES ARE THE FUTURE OF MOTOCROSS, WHY DO the manufacturers continue to develop two-strokes? For one, they're still capable of winning races-just ask Yamaha YZ250-mounted 2004 AMA Supercross Champion Chad Reed. And second, a sizable percentage of the MX bikes sold in the USA continue to burn premix, so there’s still a big chunk of change to be had.
For 2005, Yamaha showed its continued commitment to strokers by designing all-new versions of its YZ250 and 125. We aren’t just talking “new” in brochure-speak, either; both models sport brand-spankin’ aluminum frames!
The other manufacturers aren’t resting on their laurels, however, particularly not Suzuki, whose best-in-class 2004 RM250 was further improved for ’05. So while we were waiting for the new 250s from Honda, Kawasaki and KTM, we seized the opportunity for a little Gmdge Match action with the yellow and blue bikes.
It wasn’t too many years ago that the RM250 was labeled a Supercross bike, its hard-hitting motor too fierce for anyone but Pros. Those days are long gone. While the motor still has plenty of snap, it’s actually quite user-friendly nowadays. This is due in part to asymmetrical crankshaft balancing, wherein the flywheel balance is slightly offset on each side to produce a tiny variation in the phasing of the power pulses [reaching the rear tire. The goal is said to be improved traction, along 'the lines of the Big Bang principal used by MotoGP bikes. Though the crank now “shakes” as a result, the additional vibes aren’t really noticeable by the rider. What he does notice is enhanced traction, particularly when exiting slippery, hard-packed comers.
SUZUKI RM250
$5999
Ups
Turns on a dime Power everywhere Tractable with a capital T
Downs
A t-t-tad t-t-twitchy Too tight for tall riders Good luck, Ricky Carmichael!
The Suzuki’s other strength is its superb front-end feel. This pays dividends in flat, slippery comers as well as in rutted ones, where you can slot the front tire in, gas it, and remain confident that you’ll come out the other end. It steers quickly, too, the payback for that a touch of twitchiness, though it won’t break into instantaneous tank-slappers like the RMs of yore. The suspension does an admirable job of soaking up smaller bumps, but tends to blow through the stroke on bigger landings. And the bike fits shorter riders better than taller ones-new Suzuki signing Ricky Carmichael will feel right at home.
Yamaha was obviously paying attention to the trials and tribulations that Honda suffered since introducing the first aluminum-framed motocrosser way back in 1997, and strived to get its A-frame right the first time. Made from a combination of cast, forged and extmded pieces, the YZ250’s new frame is said to be 4.2 pounds lighter than its steel forebear, and the redesigned aluminum swingarm is a further 1.1 pounds lighter. We’d like to report that that weight reduction was readily apparent, but to be honest we couldn’t feel much difference once the YZ’s underside became coated with a heavy layer of mud.
We rode the Suzuki and Yamaha back-to-back at two California venues, Cahuilla Creek and Glen Helen. The former is notorious for its big, sandy whoops, and the YZ initially didn’t much care for those, swapping, kicking and generally refusing to hold its line. It also transferred jolts straight to the rider’s wrists, in spite of its new Renthal aluminum handlebars. This made us suspect that the aluminum frame might be too rigid, a la first-generation Hondas, but according to Yamaha R&D tester Steve Butler, it’s actually less stiff than its steel predecessor.
YAMAHA YZ250
$6099
Ups
Aluminum-it's not just for beer cans anymore Shorter, re-routed front brake line improves feel No more white streaks in blue plastic
downs
Aluminum frame not yet used on YZ-F four-strokes Seat cushion doesn't Aren't two-strokes dead?
Whatever the case, the YZ’s handling improved markedly the second time out, especially after we softened the compression damping in the fork. Both the front and rear suspension received comprehensive internal changes this year,
and as a result the bike doesn’t bottom hard as in the past. It still tends to deflect off the smaller stuff, though, particularly when exiting bumpy comers on the throttle. But overall it’s more stable than the Suzuki, and thus takes a bit more effort to turn.
The YZ’s engine was largely unchanged for ’05, which is a good thing, because it rips! It’s peakier than the RM, more like a 125, so takes more effort to ride fast. But if you’re man enough to hold the throttle open, the YZ can get around a racetrack with the best of them.
As for choosing which bike is best, that’s not so easy. Give us the Suzuki’s motor in the Yamaha’s frame with the Suzuki’s front end and we’d have the perfect 250cc motocross bike. Short of that, we’ll give the nod to the Yamaha-but only by the slightest of margins. Winning races will still come down to the rider.
