To vee or not to vee: Honda’s MotoGP slump

Results bear this out. Mostly. But while Honda has the right engine configuration, the great company is currently in the throes of the worst slump in its long and mostly glorious racing history, languishing a distant bottom in the constructors’ championship they have won 25 times.

The theory still adds up – that the off-beat power pulses of a pair of 90-degree vees, themselves (in Ducati’s case, anyway) with crankpins 70 degrees apart, use the tyre more effectively. Time to recover between power pulses improves traction.

This explanation was reinforced by Yamaha’s retiming of its in-line four, twenty years ago … when Rossi joined them from Honda. Instead of an in-line four’s natural two-up/two-down even firing intervals, Yamaha used a cross-plane crank, with the middle cylinders 90-degree out.

It meant the engine needed a balance shaft, adding complication and sapping power, but more importantly, it expressed its power like a V4. At the time, chief engineer Masao Furusawa explained that it also eliminated the “noise,” or flutter in crankshaft speed, generated when all four pistons reached top and bottom dead centre simultaneously, but the uneven firing intervals clearly benefited tyre grip.

There is however another important difference: a V4 has just two crank throws and two big-ends, making this heaviest single engine component shorter and stiffer, and the engine narrower, while also reducing gyroscopic effect (very considerable, at 20,000 rpm) by bringing it closer to the centre line.

These are important considerations, at the giddy limit. Nuances of balance and handling responses that affect braking, mid-corner speed, agility and corner exit. A V4 is easier to pitch in to full lean, easier to pick up again. The main cost is the more awkward packaging, and in-line four is more compact overall and generally more convenient, especially for mounting intake and exhaust paraphernalia.

For the past decade, these dynamic advantages have given V4s every title but two –Jorge Lorenzo (Yamaha, 2015) and Joan Mir on a copycat cross-plane Suzuki in 2020.

For the past couple of years though, it’s been Ducatis all the way, with the occasional interruption by Aprilia. And even more occasionally by KTM, though this more erratic success is for more complicated reasons than that their vee-angle is a slightly quirky but slightly more easily packaged 86 degrees.

A famous race engineer once told me: “What wins in racing is what won last year, plus a couple of percent.” Follow this mantra, and your 90-degree V4 is set for a long reign. But is this cast in stone?

The question mark has been set not at MotoGP, but over in the World Superbike paddock, where combatants vie on production-based machines, none of them a million miles from MotoGP prototypes. This is especially true of Ducati’s Desmosedici-alike Panigale V4. It arrived in 2022, and immediately emulated its MotoGP role model by dominating the championship. Until now.

This year, the Ducati has met its match, in the upgraded combination of BMW’s M1000RR and new rider Toprak Razgatlioglu. At the time of writing, the Turk has won the last nine races in a row, and three more before that, to handsomely outrank the dominant champion of the last two years, Alvaro Bautista, as well as his Ducati factory team-mate Nicolo Bulega, currently a distant second overall. They’re only halfway through the season, but the pattern is ominous.

The significance? The BMW (which, by the way, has no MotoGP equivalent, the German marque having so far resisted any temptation to join the senior series) is an in-line four. And it’s not even a V-clone with off-kilter firing intervals. BMW rejected the cross-plane option, preferring to rely on their experience with a conventional even-firing four.

Does this mean a sea change? Probably not, but it does fire a warning shot across the bows of the V4 armada. Furthermore, it is a wake-up call to armchair engineers, showing that foregone conclusions can fall prey to changing parameters.

What Razgatlioglu and BMW really have proved is the same thing as Rossi when he switched from Honda to then underdog Yamaha in 2004, and won at the first attempt – that it’s the rider that really makes the difference.

Yamaha have currently upgraded their long-standing in-line four, with sufficiently encouraging results to convince star rider Fabio Quartararo to renew his contract. But they, and all the rivals, will be making new engines for 2027, when new 850cc regulations take effect. It will be interesting to see exactly how they dispose the four cylinders.

Images courtesy of Motorsport Images.