[cover image courtesy of Honda VFR800]
The V4 is everything you could want in a motorcycle engine. It has been described as the perfect engine layout, comprising flexibility, smoothness, and purity of output. It is widely used in top level racing, both in superbike and MotoGP, and has had great success. It does have some drawbacks however, which need to be addressed at the design phase.
So ideal is the V4 as an engine, that top level racing has sought to either adopt the configuration (as with Aprilia, Honda, Ducati), or mimic it (Yamaha and now Suzuki). The cross-plane crankshaft inline-4 cylinder as developed and produced by Yamaha cleverly mimics the V4 engine’s firing sequence in a more compact inline cylinder layout. So what is it about the V4 that makes it such a special engine, to the degree that other manufacturers would spend millions to emulate it?