Honda Leading the V-Four Development

Despite the worldwide recession, Honda is still investing heavily in new technology with a completely different cylinder-head design for the front and rear banks as the company goes all-out to eliminate the packaging problems that have traditionally made V4 engines awkward to fit into production motorcycles.

The new Honda V4 motorcycle engine will feature an incredibly compact front cylinder head design, with just one camshaft operation all eight valves in the cylinder-head, while the rear cylinder head is a tech-fest incorporating Honda's latest variable-cylinder and variable-valve management technology. It all comes in the desire to cut precious millimeters from the engine's length and height to create a tightly packaged machine.

Honda also fiddled with the conventional layout of the V4 engine. It has also changed the engine's bore-center spacing to achieve a design that is narrow at the back, where space widthwise is at a premium, and wider at the front. Honda did this by arranging the conrods so that the pair form the front cylinder attach to the outer ends of the crankshaft, while the rear cylinder conrods are mounted closer together in the center. The result is a design that's more like a V5 than a conventional V4 engine such as Aprilia's new RSV4 where the conrods for the front and rear cylinder are alternated along the length of the crankshaft.

The shorter front cylinder heads allow the whole engine to be moved forwards, close to the radiator, while freeing up extra space above for the airbox. And the narrow-set rear piston layout maens that the frame can be drawn inwards where the rider's knees need to go, giving the feeling of a much narrower motorcycle.