Transported

The new (November) Cycle World has an excellent mid-season MotoGP review from a technical standpoint by Kevin Cameron. Some highlights:

Bridgestone vs. Michelin—Cameron explains what happened at Michelin to make them not as attentive to MotoGP riders and how the rule changes couldn't have come at a more difficult time for them. A telling example of how the Michelins fail is at Laguna Seca, where Melandri on a leased Honda but running Bridgestones was faster than Rossi on Michelins.

Valves—Honda and Yamaha also made a mistake in thinking that steel valve springs would be sufficient in the new bikes. They are both working on alternatives, most likely pneumatic like the Suzukis and Kawasakis have. Cameron noted that he could hear the Ducatis growl down the famous Laguna Corkscrew then accelerate into the next left without shifting. All others had to shift. He said the other bikes can reach 19,000 rpm, but must set more conservative rev limits in order to finish the race with the 21-liter fuel allowance.

Electronic controls—Capirossi was asked about the difference between the 990 and the 800s. He said the engine control program suited his aggressive throttle style. But, now with the required fuel-economy program, he must be very precise in an "energy-conserving, high-corner-speed 125cc style." He was wistful for the days of 500cc two-strokes that would make half the 800cc field fall off in one lap.

Speaking to Domenicali of Ducati about fuel economy, Cameron was told that Ducati employs "fuel-conserving techniques in every regime of engine operations, from idle to peak power." And, even though their engine has "very bad flat spots," they still achieve smooth torque delivery through automated throttle modulation, which is not engine retarding, which would waste fuel. He said "fast-acting throttle actuators rapidly flutter the butterflies as the engine accelerates, delivering the average torque the rider commands from the throttle grip but trimming the engine's natural peaks and filling the valleys." Their positive desmo valve drive allows high valve lifts even at 19,000 rpm and valve timings that "make big power and yet retain smooth driveability."