Honda’s V-Twin Alternative

Steve Cooper investigates: It’s late 1995 and the premier class of Grand Prix motorcycle racing is beginning to look just a little stale and stilted. The series has become a three-horse race between Honda, Suzuki and Yamaha, all with running variations on the theme of four-cylinder two-strokes. Every single machine on the track that stands even a vague chance of winning or getting a podium slot is a derivation, contraction or version of the ubiquitous V4.

Both Honda and Aprilia had independently arrived at similar conclusions based on analysis of the 250cc class – the twin-cylinder quarter-litre strokers seemed to make less of a meal of corners than the four-pot half-litre premier machines. The lithe 250s didn’t carry as much mass, were easier to brake and stabilise into turns, and only lost out when it came to absolute power on the straights and super-fast corners. It was one of those lightbulb moments that seemed to offer something for almost nothing… if you could run a big-bore V-twin engine in a smaller, lighter and less bulky frame then surely it should have real potential?

Honda jumped straight in following approval by the governing body and had the NSR500R ready for the start of the 1996 season; it also had a clever financial trick up its sleeve. Whereas the V4s were leased to various outside teams, the V-twins were there to be sold and thereby generate a significant revenue for HRC. The all-new motor ran a single crankcase with a pair of 250cc cylinders mounted at an included angle of 100 degrees. Fuel and air entered the crankcases via closely-fitted reed valves – something Yamaha had pioneered on its motocross machines almost two decades earlier.  Weighing in at just 103 kilos, the V-twin was some 30 kilos lighter than the V4s and even if it was some 50bhp down on power, the maths very strongly indicated that there were advantages to be had from the novel arrangement.

Initial trials and evaluations suggested the concept was viable and factory test riders reported the bikes were significantly easier to ride and handled better than the V4 due to the dramatic loss in weight. In the heat of competition, similar, favourable, effects were seen, whereby the V-twins were lapping as fast the V4s and, given a clear track, the new bikes were equally as effective. Japanese factory rider Tadayuki Okada took his NSR500V on to pole position for its first race in Malaysia but unfortunately had to retire during the race. With six top-five places and a second place in Australia, both rider and machine more than verified the concept of a big stroker twin.

Where the V4 required revs to deliver horsepower, the V-twins offered phenomenal levels of easily accessed torque, making them incredibly quick without the need for frantic gear changes. And because they were so much lighter, the V-twins could be ridden harder into corners, aiding a faster exit and very much in the 250 style of riding.

The V-twins were GP favourites with the fans because they were something new and fresh, offering a different and exciting perspective to 500cc GP racing and sounded so very different to the V4s. Honda sold 22 NSR500Vs before starting to distance themselves from two strokes with the advent of the later, one-litre four strokes. The big bore V-twins had proved to be an entertaining and novel idea, but just like Aprilia with its similar RSW2-500, it’d seen the flaw in the supposition that less might genuinely mean more. The big V-twins were truly viable when they were on a run, at the head of the pack or not surrounded by the V4s, but as soon as the 500 twins got caught in a melee of machines, the multi-cylinder bikes just had that competitive edge. Just two NSR500Vs were built for the 2001 series to be ridden by the Shell Advance Team; after that the race tracks were arguably the poorer for the lack of what were really big bore 250 twins with a whole bucketful of attitude!

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