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RACE WATCH

Roberts, March racebikes near completion

Inquiring minds want to know what's happening with two ambitious racebike projects: the Team Roberts three-cylinder 500cc GP bike being built by Tom Walkinshaw Racing (TWR) in Britain, and the March Superbike, likewise an English project.

Chuck Aksland at Team Roberts revealed the engine is running now, but said only, "It's a three-cylinder, and that's about all I can tell you."

Asked about rumors that sponsors wanted to delay the machine one year, he said, "Our plan right now is to run it in all the GPs. Initial testing will be in mid-to-late February."

Aksland also told Cycle World the design concept was worked out by longtime Roberts engineering staffers Mike Sinclair, Warren Willing and himself. "I

can't really say too much about the chassis," he continued, "except that the whole bike was thought of as a package. We struck a deal with TWR to draw and manufacture the design."

A Triple's attraction is the 33-pound weight break given it by the FIM. The lower revs imposed by a Triple's longer stroke suggest 150-160 horsepower as its likely peak output, but the power-to-weight ratio will probably equal that of the 180-horsepower, 286-pound Fours. A lighter bike, with equal acceleration, is a better tool.

Aksland said, "The idea is to make it

the same size as a 250." Such a reduction in frontal area, combined with 155 horsepower, puts potential top speed in the low 180-mph range-close to that of the bulkier Fours.

Will it work? The 220-pound 500 Twins-Honda's NSR500V and Aprilia's RSV400-have made an impression but haven't been able to win a race. Power-to-weight is substantially better for the Triple. Combine that with Roberts' known respect for a Triple's acceleration and you have the makings of a fascinating gamble.

CW also spoke to Les McTaggart, director of the new March Superbike project (see Roundup, February, 1997), based in Bicester, England. Engine designer Al Meiling believes that the design possibilities of four-stroke V-Twins are nearly exhausted, and that the potentially higher rev ceiling of a 750 Four isn't yet fully exploited.

Of current progress, McTaggart said, "We have a fiberglass model to use for fitting and styling, as we continue to do the design of the motorcycle. A real prototype should be running by

the end of March. We'll shortly have a full-size model (for wind-tunnel use) to check cooling air velocities."

March has two or three engineers working on the chassis, "people with strong backgrounds in motorcycle experience," added McTaggart. He was careful to distinguish engineeringstress computations, aerodynamic analysis and so on-from specific trackside experience. Both, he noted, are essential. The swingarm, made in composite as apparently will be the rest of the chassis, will not be a single-sider. Once approached by persons wanting a composite duplicate of an aluminum single-sided swingarm, McTaggart said, "I was amazed at the mass of the thing. A conventional swingarm makes more sense to us."

A V-Four was rumored as the power source, but a transverse inline-Four is more likely. "We're still evaluating which is better," said McTaggart. "It could be either. AÍ felt an inline was the best compromise, but a V-Four offers a better package. We're trying to keep an open mind as late as possible."

Although such scheduling would be unrealistic for a major manufacturer, Meiling is accustomed to the lightning-quick production schedules of F1 racing, in which a chassis goes from scratch to final product in 12 weeks, a complete car in 4-5 months. "I'm hoping we'll be able to use some of the technologies from other areas," McTaggart said, suggestively.

This could mean pneumatic valves, which have been a powerful tool in F1 's successful assault on higher rpm. Without metal valve springs, many high-rpm problems melt away. It will also mean use of Meiling's preferred ignition of three sparkplugs per cylinder-a way of speeding combustion in the wide, low-ceilinged combustion chambers that go with the short strokes and big bores high revs require. The engine will have four valves per cylinder-F-1 experience with five or more

has not been encouraging. The radiator will be fully ducted and located under the seat, as on the Britten V-1000.

Power from higher revs? Both Suzuki and Kawasaki have now dipped a toe into the inviting pond of shorter strokes, only to find less power. Current Fours redline near 15,000 rpm, but develop their power 1000 or more rpm below that. Rob Muzzy speaks of a "friction barrier," and McTaggart agreed, saying, "The restriction, currently, is in valve gear." In F-l, redlines for 300cc cylinders are up above 17,000 rpm. March offers the tantalizing possibility of an F1/Superbike synergy. "We have great respect for the Japanese and what they've done," McTaggart concluded. "We won't underestimate the task."

Lewis fourth in Dakar Rally

Cycle World's Off-Road Editor Jimmy Lewis finished fourth overall at the 1997 Dakar-Dakar Rally. Yamaha's Stephane Peterhansel was victorious for the fifth time, and Cagiva-mounted Oscar Gallardo finished second. Peterhansel's teammate, David Castéra,

rounded out the top three.

Riding in his second Dakar Rally (see "Dakar Diary," May, 1996), the 28-year-old Lewis, aboard a factoryprepared KTM 640, won the llth-day, Kidal-to-Timbuktu stage. He was the only rider to navigate the 358-mile section, which route director Patrick Zaniroli dubbed the "most testing of the year," in less than six hours. "I had always wanted to ride the Dakar," Lewis said, smiling broadly. "But it's a dream to win a stage."

Look for a full report in next month's issue. □