Riding the Works Specials
Riding the Works Specials
The Nastiest Dirtbikes on Earth
CW RIDING IMPRESSION
Ron Griewe
JUST LOOKING AT PHOTOGRAPHS OF works motocross bikes is enough to set off salivary glands. Handcarved pieces of aluminum and magnesium are used for the triple clamps, shock-linkage arms and brake-caliper carriers. Ultra-expensive titanium nuts and bolts are commonplace. Expansion chambers flaunt glorious welds. And get a load of those trick, high-dollar forks and shocks. Heaven, pure off-road heaven.
Can any privateer expect to be com petitive against such bikes? Do these labor-intensive machines give a rider a tremendous advantage over some one on a well-prepped production bike? Or are these factory specials simply ego boosters for star riders and showpieces for the factories that build them?
That's just what we intended to find out by riding the bikes that had fin ished 1-2 the previous day at the sea son-opening 500cc USGP, held on Southern California's Glen Helen racetrack. Jean-Michel Bayle's winfling Honda and Jeff Matiasevich's second-place Kawasaki were deliv ered to Cycle World in the very condi tion they were in after the final moto.
J ean-Michel Bayle, the French fac tory Honda rider who now resides in Southern California, trashed ex isting records in 1991 by becoming the first rider to win three AMA na tional championships-Supercross, 250cc and 500cc-in a single year. Prior to these feats, Bayle was the 125cc World MX Champion in 1988 and the 250cc World MX Champion in `89. Allege that he's currently the best motocross rider in the world-maybe the best ever-and you won't get much of an argument
Bayle, 23, rode his first 500cc GP last year at Glen Helen, where he won overall after trading moto wins with Kawasaki's Jeff Ward. This year, the easygoing Frenchman won all three 25-minute motos with little difficultyeven in the second moto, where he rode the last 10 minutes with a flat rear tire.
Five-time World MX Champion Roger DeCoster, currently American Honda's motocross coordinator, spot ted Bayle's natural ability during the youngster's first trip to the U.S. Says DeCoster, "Jean-Michel seems to go very fast without exerting much ener gy, he has a very positive attitude and he is very good at reading the track. When the lines he has been using be come rough, he just changes to smoother lines."
That adaptability may lead Bayle away from motocross. "When we were testing motocross bikes in Japan, Jean-Michel talked the factory into letting him try a works 250 road-
race bike," DeCoster says. "Although he had never ridden a steetbike or roadrace bike before, within two hours, Bayle was turning faster lap times than those of the factory test riders who know the bikes and the track."
With that kind of talent, Bayle should well be able to win grand prix motocross races on a well-prepped production CR500R. But, when you have a rider that's considered the best in the world riding on your team, it makes sense to provide him with a special machine.
Surprisingly, Bayle's USGP bike really wasn't all that trick. Bayle's 500 is the same bike he will ride in the `92 nationals, which means it has to be production-based: The body work, frame, swingarm, engine and five-speed transmission are stock. The cylinder has minor porting changes, the head's combustion chamber has been altered, a Pro Circuit pipe is used and the engine's sidecovers are magnesium HRC units. That's it.
Some local California Pros have more radical engine modifications than does Bayle.
More exotic, however, is the factory Showa suspension. Especially tasty are the machined aluminum shocklever arms, which retain the standard progression ratio. There's also an alu minum glide plate under the engine and an aluminum guard mounted under the clutch cover to prevent rock damage. Thicker-core, unpainted alu minum radiators provide additional engine cooling.
Perhaps the neatest thing on Bayle's bike is its rear brake. "Bayle uses the rear brake a lot," says DeCoster, "He rides the brake across the bumps and uses it for balance and bike position while on the track and in the air." After the standard brake faded halfway through last year's 45-minute GP motos, Honda made Bayle a oneoff rear caliper that's machined from an aluminum block. This caliper fea tures massive cooling fins, a brass piston and brake pads with consider able friction area. A larger-than-stan dard rotor also helps dissipate heat.
Bayle's CR500R shows that a lot of time has been spent fine-tuning the suspension: Small bumps disappear, landings from sky shots don't jar the rider, and the suspension never gets confused. Off-road suspension just doesn't get any better than this.
Less favored by Cycle World test riders was the production-based en gine, which snarled like a tiger off the bottom, followed by a midrange roar in which all hell broke loose. Thrilling, but unless you're in top shape, the potent powerband soon turns legs to jelly and arms to rubber.
J eff "Chicken" Matiasevich is one of America's hottest motocrossers. Spirited and fun-loving, Matiase vich usually displays an ear-to-ear smile, though that playfulness changes to a take-no-prisoners atti tude on the track. Determined, radical and wild, the 23-year-old Southern Californian cares only about winning.
Kawasaki's best full-on motocross bikes are made in-house at Kawasaki Motors American headquarters in Cal-
ifornia. Like Bayle's Honda, Matiase vich's SR500-SR for Special Racerbegan life as a production KX500. Factory KYB suspension, magnesium triple clamps and abundant use of tita nium bolts initiate its transformation to factory racebike. A larger clutch is shielded by a magnesium cover; the engine's centercases are bored to ac cept larger main bearings; the cylinder is ported; the head is modified; and a Kawasaki factory exhaust system is installed. The frame is stock, but its production aluminum swingarm has additional gusseting to eliminate flex. Factory brake master cylinders offer increased braking power.
Riding Matiasevich's SR500 really wasn't the thrill that we had imag ined. The engine vibrates even more than that of a KX500, the clutch pull is extremely heavy, and the suspen sion only moves after landing from second-story ledges. Powerful and wild best describes the SR's power. "Yeah, it's a handful," admits Matia sevich, "but I don't want anyone to outrun me on the straights. And they don't."
Cycle World test rider Gordon Ward, wide-eyed after riding the SR said, "I can't believe this bike. Its en gine vibration is terrible, I can barely pull the clutch lever and the suspen sion doesn't even move when cross ing the small stuff. Man, I almost feel sorry for Jeff; I don't know how he rides that bike. No wonder he looks kind of wild. I'd take a stock KX500 over that thing any day."
W hich brings us back to our opening question about facto ry bikes. After riding the two best 500s in the U.S, we'd have to conclude that, as alluring as these wonders of mechanical ingenuity are, the average racer will go faster on a production motorcycle that's had its suspension and engine carefully ad justed and tuned for his riding style and abilities. The perfect motocross bike isn't necessarily one that is load ed with expensive, beautifully crafted parts. Rather it's one that fits its rider well, one that he can ride fast without fighting. A factory racebike that's been set up for a particular racer's preferences may well be a motorcycle that the average rider would find un believably hard to live with.
Matiasevich's bike is the perfect ex ample: It flat intimidated CW's test riders. But the Kawasaki was set up for Jeff Matiasevich. As alien as the SR felt to us, it suits him fine, as he proved by smoking his way to second overall at Glen Helen, racing against the best 500cc motocross bikes and riders in the world.
So, the next time you find yourself drooling over a factory GP motocross bike, accept it for the striking, power ful showpiece that it is, then take a good hard look at what its rider is doing on the track. That's where you'll find the real secrets to winning races.
