Chasing perfection: Honda’s oval-piston NR750 at 30

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In October 1991, the most exotic and most expensive production bike ever been produced by any Japanese brand was launched, embracing a level of tech which – even today – seems extreme.

The Honda NR750, aka RC40, was the first – and so far, only – opportunity for customers to experience the fruits of Honda’s obsession with the holy grail of oval-piston engineering.

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It was a pursuit which began as a rule-bending exercise, but also one which had been determined to offer significant advantages, beyond the initial objective of satisfying Soichiro Honda’s distaste for two-strokes, by developing a four-stroke to go racing with in the 500GP class. Honda by then held over 200 patents on aspects of the NR750’s engine design alone.

The NR750 was an important step forward in two-wheeled performance, as the first Japanese sportsbike to be fitted with fully mapped multipoint fuel injection, and the first from any country to use an upside-down fork, carbon-fibre bodywork, titanium anything, side-mounted radiators (later copied on the Firestorm and VTR1000 SP-1/2), and exhausts under the seat.

And in terms of styling, 30 years onwards the NR750 streetbike is still considered one of the most seductive pieces of two-wheeled splendour ever seen. The work of Honda’s design team, headed by Mitsuyoshi Kohama even inspired the Michelangelo of the motorcycle, Massimo Tamburini, to copy it with the Ducati 916.

Project leader Takeo Fukui who went on to head Honda

Yet just 322 NR750s were ever made, with 220 built in 1992 - of which 20 were the 100bhp RC41 variant for the French and Japanese markets, plus 102 more bikes in 1993, before production was terminated as orders dried up. 

But maybe some explanation for that was the very thing Honda were so proud of – the NR750’s seamless power delivery throughout the rev range. The closest thing I can equate that to is riding a Norton Rotary racer of the same era. Like the Wankel-engined bike, the NR made power practically from off the clock.

This ultra-linear, ultra-smooth, progressive delivery was also ultra-deceptive, that even as the tacho neared the 15,000rpm redline, there was no sign of strain or effort – just liquid revs, silently and effortlessly delivered.

Honda NR750 oval piston 8-valve engine

Still, the Honda’s Showa suspension was outstanding. The NR’s meaty 45mm upside-down forks delivered outstanding compliance and lots of feedback, even when exposed to the massive braking potential of the 310mm floating front discs and their four-piston calipers.

As I’ve subsequently found in the real-world riding a Spanish friend’s NR750 on twisting mountain roads, the extra safety margin these offered in road terms was a genuine plus, but not to the point of overkill or over-sensitivity.

The NR750 wasn’t a razor-sharp race replica like the RC30, and though it was a lot more relaxing and comfortable to ride up to a certain level, beyond that it was more sports-tourer than superbike.

Honda NR750 with its bodywork removed

It was very comfortable, handled superbly, braked as well as a superbike, had lots of sensible touches like the digital speedo, and was extremely satisfying to ride, if a little heavy to swap direction on.

The styling is sensational even 30 years on, and back then for that hefty price tag, you had the satisfaction of knowing that beneath the high-class threads lay the cutting edge of four-stroke oval-piston fuel-injected engine tech.

Maybe the NR750 wasn’t a bargain, exactly – but maybe not such a bad deal after all, especially with examples being advertised today for upwards of £100,000.

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Watch Michael Neeves compare the NR750's predecessor, the RC30, to a Modern Ducati Panigale V4R in this video:

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Alan Cathcart

By Alan Cathcart