Keith in Jersey asks Kevin Cameron:

Did you ever think that you would see the day when Honda and Yamaha are the D-class constructors in MotoGP? What combination of technical, organizational, and philosophical decisions led them to this humbling position?

One distillation of how MotoGP bikes should be built comes from crew chief Jerry Burgess, who worked many seasons with Valentino Rossi. His view was that a constructor must build a motorcycle that could be ridden by any top rider.

That’s a lovely ideal, but how then do we cope with what Colin Edwards, Jr had to say about being teamed with Rossi as tire tester (a role for which he was greatly esteemed by Michelin) for the pivotal 2004 season?

Ichiro Yoda had been in charge of Yamaha’s MotoGP development in the first two years of the new series, 2002 and 2003. Because results did not materialize it was decided to put in the company’s one-man tiger-team, Masao Furusawa. His specialty was NVH – noise, vibration and harshness. Riders of the new four-stroke had found they could not accelerate with the Honda V4. Furusawa knew that all four pistons of in-line fours with flat crankshaft stop and re-accelerate twice per revolution.

This was a large exchange of energy between the pistons and the crankshaft, causing substantial cyclic “flutter” of rpm. Could that flutter be interfering with tire grip?

Could it interfere with the rider’s ability to sense tire grip?

Furusawa had four engine combinations built. As he apparently had reservations about five valves, these were as follows;

Flat crank, five valves per cylinder.

Flat crank, four valves.

90-degree crankpin spacing (so-called “cross-plane crank,” five valves).

90 degree crank, four valves.

When Rossi tested these four combinations, he liked best and went quickest on #4. During a crazy and eventful season, Rossi was able to take the championship.

By changing crankpin angle from 180 degrees to 90, Furusawa stopped the pistons from exchanging energy with the crank, to exchanging it with each other. This was because, when one piston was at TDC or BDC, the next piston in line was at close to maximum velocity. With pistons exchanging energy with each other instead of with
the crank, the crank’s rpm flutter essentially disappeared. Yamahas could now accelerate as strongly as V4s.

Now for the really strange part. Edwards was a proven champion, having taken World Superbike on Honda RC51 in 2000 and 2002. But he was unable to get similar results on the Yamaha M1

When I asked Rossi and Edwards, on separate occasions, their tire preferences, here’s what I got.

Rossi, who excelled in long, fast corners, said he needed a stiff tire construction so that the tire could remain stable through such corners.

Edwards wanted a large-section but soft-construction tire, as it was his style to brake late and hard, arrive at a zone of fastest turning, get the bike mostly turned in limited distance, then use the large grip of this tire to accelerate very hard to recover corner exit speed.

When I asked Rossi what happened if he tested Colin’s chosen tires, he told me, “The bike jumps sideways.” In other words, the softer carcass was buckling under sustained high-speed turning.

What this showed was that tire and motorcycle manufacturers did not know much about differences in rider style. Neither did I! But they would teach me.

Later I would talk with other riders, who were quite pointed in describing two general ways to ride a motorcycle, and the qualities that had to be engineered into it to support a rider’s style.

The corner-speed rider—Rossi was one and especially so was Jorge Lorenzo—needed a bike that could generate and sustain peak tire grip through long fast corners. During the 1990s it was discovered that this required that the chassis be given enough lateral flexibility to let its tires, and maximum lean angle, move up and down over pavement roughness (rather than stiffly leaping from crest-to-crest as especially stiff chassis did, generating poor grip in the process. Such bikes are built to enhance stability to remain near peak grip all the way through long corners. So they are longer in wheelbase, a bit lower, and have conservative steer geometry. They are ridden smoothly. High corner speed means less need for hard braking or acceleration.

This came to a head in 1992 when Yamaha built its 500 GP chassis with internally reinforced extruded rectangular side beams (rather than their formed-and-welded sheet aluminum “perimeter” structure. This chassis was stiff in longitudinal bending, in torsion, and in lateral bending. After practice at Eastern Creek in Australia, rider Wayne Rainey told the press, “We have chatter, we have hop, and we have skating. And so far we haven’t found a solution.”

Now think about the point-and-shoot rider. Kenny Roberts brought this style to the GPs from dirt-track. In this style, which works best in smaller corners in which no steady state is reached, the rider approaches the corner, brakes late and very hard, yanks the bike around quickly, lifts it and accelerates away very hard.
To make the necessary quick maneuvers to get the bike turned, steering rake angle is steep. The bike is taller than a corner-speed bike – to achieve the complete weight transfer needed to get the front tire gripping quickly (tire temperatures rise and fall down every straight, through every corner – tire do not just ‘warm up’ and perform uniformly after that).

Cal Critchlow also rode the Marquez-style Honda, calling it “very physical” to ride. We have all seen the videos of Marc braking with rear wheel in the air (Razgatlioglu style), then letting the rear swing outward, and setting it down already sliding. Only Marc could do this, on a bike engineered for it.

To brake this hard requires a stiffer chassis to prevent braking instability (Max Biaggi held forth on this in 2002, saying that once started, the oscillation could quickly diverge to very large amplitude and throw him on the ground). But a chassis with high lateral stiffness is handicapped in long fast corners because it’s too stiff laterally to allow its tires to rise and fall over pavement texture at full lean angle. Result? Lower grip in faster corners.

The corner-speed style comes from learning on lower-powered machines (the 125s and 250s of the pre-MotoGP era) which cannot accelerate as required in point-and-shoot.

Colin, a point-and-shoot man, found it very difficult to get anywhere with Yamaha’s efforts to give Rossi (who had been hired to win the championship) the motorcycle he needed.

Another example. Cal Crutchlow told me, “I came to Yamaha from British Superbike, so naturally I tried to ride it that way. It wouldn’t do it. I had to learn to ride it its way.”

Why don’t riders just do what he did? Ride the bikes they are given in the style they demand? Famous experiments were done in which people tried to ride bicycles whose steering had been reversed – so when you turned the bars to the right, the front wheel turned to the left.

So powerful are the subconscious learned responses necessary to ride a bicycle that it took those who persisted six months to learn to ride the backwards-bike. And once they had learned it, they could no longer ride a conventional bike. This was underlined when Lorenzo was hired to ride Ducati. At first it was disaster, but his powerful talent eventually (18 months that neither he nor Ducati could afford) made the leap and won three GPs. But by that time rider-team relations had so soured that they separated.

The people who understood these things were all riders and trackside people, but the decisions of whom to hire as riders were made at management level. As former racing manager for American Honda, Gary Mathers once said, “Engineers take the data, and in six months are ready to file their report.”

So here’s how I see it. When Marc Marquez had his accident, Honda decided they had to alter his bike to make it rideable by others (during Marquez’s early and middle career that the other riders on Honda were getting nowhere).

Next example. In 2021 here came Fabio Quartararo on the traditionally corner-speed Yam, winning the world championship. But on Yamaha as well was Maverick Vinales, saying he wanted to ride “more aggressively.” This means harder braking, harder acceleration, which don’t work on a corner-speed bike, as noted by Crutchlow, above.

The changes to the Yamaha resulted in five years of Quartararo’s arriving at pre-season tests to find that the new bike lacked horsepower and rear grip. It does to this day.

I suspect that Yamaha, too, had begun a process of trying to make a bike to please every rider.

When Marc Marquez became fit enough to ride again, he said he no longer knew what the bike given him would do next. It is essential that the rider have confidence in how the bike will behave, and knowledge of its “signals” to the rider. This is why Mick Doohan was so emphatic during his riding career that no changes to his bike be made without his knowledge and permission. With a new fork or rear suspension linkage or engine map, everything is disturbed and the rider must learn it all again. As Doohan said, “I’m here to win the race, not to test hunches for engineers. You have test riders for that.”

He and other top riders need a bike whose responses they know in detail.

Now add the management style of Japanese engineering. Every couple of years, engineers are moved on—perhaps to outboard motors or lawn care equipment. They take with them all their work notes and any relationships they have had with the rider. A fresh group comes in who must learn afresh. The stated purpose of this policy is to familiarize engineers with all of a company’s activities, ensuring that stale ideas are replaced with fresh ones.

Honda and Yamaha lost the all-important rider-machine connection. Despite hiring European engineers to help with this, MotoGP has become and remains a European series—as it previously was from 1949 to 1975.

Honda have made some progress. Some theorize that Yamaha are focusing on next year. Will they both surprise us with competitive new bikes in 2027?