Honda NR750: asking price $150,000

Indeed, you read it correctly. Oval pistons! The Honda NR750 is truly a technological marvel. The world’s only motorcycle with four oval pistons arranged in a V-shape, eight valves per cylinder and two connecting rods per piston. Produced in 1991 and 1992, because Honda wanted to compete in the World Superbike Championship with this bike. That was only possible with racers that were based on street versions.

Honda NR750 at the time 150,000 guilders

The street version of the Honda NR750 cost 150,000 guilders in the Netherlands at the time. The buyers weren’t exactly lining up. Nor in other countries. The engine was built in a limited edition of 500 units only to order. In the end, some 300 were assembled.

Unique specimen

In fact, the one you see here, offered at Iconic Motorbike Auctions in California, is still new. 5 km is only on the counter and they were probably made pushing. After all, the battery is never filled with the battery acid provided. So in any case, the engine was not started with this battery. Judging from the photos, you can already see that the NR750 is in showroom condition.

Descendant of Honda 500cc road racer

Honda started using oval pistons as early as 1979. The Japanese motorcycle manufacturer then presented a four-stroke racer for 500cc road racing. By then, that class was completely dominated by two-stroke racers. Honda fully believed in the power of four-strokes. However, to get the required power from a displacement of 500 cc, very high speeds were required. That succeeded only with small pistons and valves, as in a V8, for example. Honda found the solution in a V4 with oval pistons and eight valves per cylinder, and that block was presented in the Honda NR500 road racer.

15,000 rpm!

The NR500 was capable of 15,000 rpm. Expectations were high, but it failed completely. There were often technical problems. Only once did Honda manage to qualify for a race, but most of the time the engine failed afterward. Never achieving World Cup points, the project was cancelled in 1982 and Honda still opted for two-strokes with the presentation of the NS500.

Technical issues

Giving up, however, is not an option at Honda. A racer with oval pistons was nevertheless sent back on the track in 1987 and in the 24 Hours of Le Mans. That was the NR750 racer, but it did not make it to the finish line due to a broken connecting rod bolt. The Le Mans adventure, however, was a prelude to participation in the World Superbike Championship with the NR750, which did require production of a street version.

Progressive technology

For 150,000 guilders you got an almost entirely hand-built engine with numerous technical marvels. These included the for the time unusual single swingarm, electronic fuel injection, fully adjustable damping and use of carbon for the fairing and other components. All to get the weight as low as possible (222 kg dry). The engine was supposed to produce 150 horsepower but it ended up being 125 in the production version.

Myth makes Honda NR750 iconic

Participation in the World Superbike Championship did not materialize. In the end, the power proved insufficient and the machine was also too heavy. The Honda NR750 did succeed 100 percent as an iconic motorcycle because of the mythical story behind this street machine. From a manufacturer with a deep and well-nigh sacred belief in four-stroke racers. That makes this 1992 engine valuable. By the way: two-stroke did eventually lose out to four-stroke. In road racing, four-strokes are now the norm, but not with oval pistons, but round ones. And Honda is running full throttle in the world’s top four-stroke racers.