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Honda RC40 NR750

Profile - Honda RC40 NR 750

Honda RC40 NR 750

How much for the oval-piston wonder?

by Guy 'Guido' Allen; pics by Iconic Motorbike Auctions & Honda (June 29, 2020)

What would you pay for a good example of one of the most exotic production bikes ever from Japan?

Enjoying a mythology all its own, Honda's ultra-exclusive NR V-four 750 has ranked among the most expensive 'production' motorcycles (just 307 examples of the road bike were made) in the world.

It was the factory's way of signing off on an ambitous but arguably flawed project which cost the company a small fortune over time. It first emerged as a four-stroke challenger to the two-stroke-dominated 500cc grand prix world championship. That in itself - pitting a four-stroke against two-strokes with the same number of cylinders and same engine capacity - was a monumental challenge.

However Honda and Honda Racing Corporation (HRC) engineers have a long-held tradition of tackling ambitious projects. Their solution was innovative. Its aim was to provide the advantages of a V-eight while still limited to the four combustion chambers required by the GP rule book.

Honda NR engine parts

To that end the pistons and cylinders developed over time into an oval configuration, each piston running twin connecting rods, with eight valves per cylinder (32 in all) run by dual overhead cams with gear drive. To get power, the design had to rev to levels that were at the time considered statospheric, 20,000rpm and over. That reaped around 130hp.

The initial rolling chassis ran a monocoque frame, though that changed to a more conventional approach, in part because the monocoque made life difficult for race mechanics.

Honda NR500

The NR500 (above) debuted at the British Grand Prix of 1979, with two examples in the experienced hands of riders Mick Grant and Takazumi Katayama. Grant crashed on the first lap, thanks to an oil spill of the bike's own making, while his team-mate retired some laps later with ignition troubles. An expensive and not very promising day at the races.

Honda persisted with variations of the design, one of which was ridden by Ron Haslam in a couple of events in 1982. They were to be its last GP outings. Instead, the company had turned is attention to the wildly successful NS500 two-stroke triple, the bike which launched Freddie Spencer into the world GP record books.

However the NR story was far from over. A 750 racer was developed, far more conventional in appearance that its early ancestor, and was campaigned with moderate success. Australian rider Mal 'Wally' Campbell and team-mate Rob Scolyer rode the machine in Swann series races with respectable results. In 1987, Campbell managed the bike's first high-level race series victory, in a Swann round at Calder Park Raceway.

Honda NR750 racer

Campbell was also involved in a tilt at the Le Mans endurance race of that year (above), qualifying the machine in second place. It suffered mechanical failure in the race.

By this time Honda was making great strides with its more conventional V-four VF series (RC30 and its successors) and the writing was on the wall for the eight-valver. At this stage it was producing around 165 horses at 15,500rpm in sprint form, or 155 in endurance form. It weighed a mere 158kg, with lights and generator.

Its finale was the bike you see at top and in the gallery below, the street version, known as the RC40 or simply the NR, sold in the 1992 model year. Running a version of the 32-valve oval-piston powerplant, it claimed 125 horses at 14,000rpm, a little shy of the 15,000rpm redline.

For a road bike of the day, it had numerous other exotic features, such as the single-side swingarm, loads of carbon fibre in the bodywork, a high-end digital and analogue dash, plus a titanium-coated screen. It was hugely expensive, at around US$50,000 (Au$73,000).

Sadly, we suspect a lot of the 307 made were quietly put away as investments, rather than seeing even minimal use on the road. Examples have been popping up on the market with surprising frequency in recent years.

In 2017, Coys in the UK sold one with little or no use for US$67,000 (Au$97,000);

In 2018 Bonhams got US$77,000 (Au$112,000) for an example with 1400km on the odo;

Mecum scored a staggering US$181,500 (Au$264,000) for an unused example at Las Vegas in January 2019;

Meanwhile Iconic in the USA had an unused Japan domestic market version (different specs) at US$127,000 (Au$184,000).

And the one you see in the gallery below? That was up for online auction in June 2020 through Iconic and attracted a top bid of US$79,000 (Au$115,000), which was below reserve. It was another unused machine, though it had suffered some minor transit damage which had been repaired but was still visible.

The NR swan-song was a fitting end to a notoriously tough project and has continued to sell for more than it cost new. You have to say, despite that, the financial return has not always been fantastic. Which to our way of thinking gives you one more reason not to leave it in the box, but to get it out and ride it...

Honda RC40 NR750

Honda RC40 NR 750

Honda RC40 NR 750

Honda RC40 NR 750

Honda RC40 NR 750

Honda RC40 NR 750

Honda RC40 NR 750

Honda RC40 NR 750

Honda RC40 NR 750

Honda RC40 NR


TYPE: Liquid-cooled, DOHC eight-valves-per-cylinder, 90-degree V-four oval pistons

BORE & STROKE: 101.2 x 50.6 x 42mm


FUEL SYSTEM: EFI, 8 x 30mm


TYPE: six-speed, constant-mesh, 



FRAME TYPE: Steel tube

FRONT SUSPENSION: USD Showa telescopic fork, 45mm, full adjustment
REAR SUSPENSION: Showa nitrogen-charged monoshock, full adjustment 

FRONT BRAKE: 310mm discs with 4-piston Nissin calipers

REAR BRAKE: 220mm disc with 2-piston caliper


DRY/WET WEIGHT: 223/244kg



FRONT: 130/70-ZR16
REAR: 180/55-ZR17


POWER: 92kW (125hp) @ 14,000rpm

TORQUE: 66Nm @ 11,000rpm


PRICE US$50,000 (Au$73,000)

Ed's note: You can find a long and detailed development history at the motorcyclespecs site, here.






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