Intermot Musings
Intermot musings
TDC
Kevin Cameron
THE AIRLINER RUSHED AND ROARED over the dark Atlantic, the Big Dipper out my window rotating fast as I napped. As we moved toward the hidden sun at double-speed, I could see a ribbed cloud layer far down, looking like sand rippled by water. More light and more travel revealed German farm country, whose rectangular fields suggested an endless exhibit of furry rug samples. Then Munich airport and the boredom of customs officials and tired travelers. Bus and subway take me to the giant Intermot motorcycle show. This is total immersion-10 or 12 huge, 747-sized hangars on the site of the former airport, now transformed into a great commercial exhibition facility.
There is a schedule-a Ducati luncheon with excellent soup, garnished with broiled scallops. There are Japanese journalists on my left, Finns across the table. It took three buses to bring us all. I hear about the new, more durable air-cooled “Dual Spark” engines and modular production, which allows more people to work on seven subassemblies than can crowd around one bike on an assembly line. In the evening, another major manufacturer’s new-model intro, a heavily catered affair, access to which is controlled by security skinheads, fit-looking young men in suits, firmly insisting everyone have a valid invitation. Can’t be too careful in these troubled times. Inside, we hundreds of journalists receive the action of the usual thunderous music and dry-ice smoke, with gold-leaf-clad fan-dancers writhing on platforms. An elaborate stage production follows, employing at least 30 more dancers, slick, pneumatic “presenters,” and almost no actual information. How do we translate all this-cocktails, hors d’oevres, noise, flesh and color-into useful product information? Has that been forgotten? I pine for the lost days of 20 years ago, when manufacturers brought just the new bikes, real engineers to talk to and lovely line art illustrating the new features. Times change; now it’s all MTV and hard-to-explain 40-horsepower scooters.
Info there was, but it was a hike to see it all, pavilion after pavilion. Kawasaki’s latest MotoGP prototype is here, its angular seatback looking as if made from Masonite plates, cleverly joined, sanded and painted green. The ZX-7RR chassis beams are gone, and the front of the fairing is supported by an RC51like carbon air duct that joins to the steering head, feeding engine intake air around it. The engine is sandcast, largely invisible, but unlike earlier illos it now has an exhaust system. The new 600 is here, too, with its inverted fork. Why be first with this more expensive fork in a priced-to-sell class? Front tire chatter is the bane of 600cc racing, and in 600 Supersport if you don’t win races, sales droop. This fork’s stiffness, arising from the large diameter of its upper tubes, can put bending frequency above that of tire bounce frequency. If the two can no longer cooperate, it’s less likely that either can build up to a disturbing amplitude.
Another march brings me to Honda, a vast flat area dotted with product. Dancers in street clothes are practicing vaults and handstands on a few of the bikes, preparing for their show. The leader, a tiny woman, calls out commands in German. Over behind the new CBR600RR is its supposed inspiration, the RC211V GP bike with its compact V-Five four-stroke engine. I want to know the wheelbase, because this bike looks so long in all its photos. I have to wait to move up to the barrier, fumbling among my golden Euro coins for my tape measure. Wheelbase is 573/4 inches, or about 3 inches longer than has been usual in roadracing’s top class. The last time there was a GP bike this long, it was Kawasaki’s KR500, ridden by Kork Ballington in the early 1980s.
What does it mean? It means someone at Honda thinks about fundamental barriers to quick lap times. Everyone else accepts that bikes must have short wheelbases to turn quickly. That’s well and good, but if you think about dragsters, it’s clear that the shorter the wheelbase, the lower the rate of acceleration that can lift the front wheel. That acceleration rate-I call it “the wheelie limit”-is of the order of 1.25 g for conventional GP bikes, and can be maintained by them up to just over 100 mph. This, in turn, means that no matter how much power such 54-inch-wheelbase bikes are given, they must all accelerate equally hard up to the highest speed at which they can wheelie (when power is lifting your front wheel, the higher the wheel goes, the less power it takes to keep it there, meaning once your wheel comes up, you can accelerate no harder).
Other makers all adopted chassis based on their proven two-stroke GP bikes-short wheelbase, wheelie-limited acceleration up to 105 mph and all. Honda evidently decided to change the basic compromise in favor of stronger acceleration in this range. In effect, they made their bike into a bit of a dragster, with its longer wheelbase.
Now how did they make their dragster steer, with its longer chassis? A few years ago, I thought the short wheelbase acceleration/steering problem would be resolved by variable ride height-low for acceleration, high for cornering. Honda has done it more simply, as Dan Gurney has done with his recumbent Alligator motorcycle. Because the ’Gator is long and low, it has excellent initial acceleration and braking. To compensate for its long wheelbase, it has low roll inertia. It is extra-flickable because its rider sits in and not on it. Honda has trumpeted the compactness of its 21IV engine by supplying a drawing of the major engine types, each inscribed within a circle. The 21 l’s circle is smallest. This is not the real point. More important is that this bike’s major masses-engine, underseat fuel tank and rider-are closer to its roll axis, a horizontal fore-and-aft line drawn through its center of mass. A long bike, if it can maneuver with shorter ones, can out-accelerate and out-brake them. And the 211V does just that.
