Some 25 years later, we look back at the release of the oval-piston 1992 Honda NR750 street bike.
1992 Honda NR750 RC40
Engine: 748cc 90-degree water-cooled DOHC oval-piston V4, eight titanium valves and two titanium connecting rods per cylinder, 101.2mm x 50.6mm x 42mm bore and stroke, 11.7:1 compression ratio, 125hp @ 14,000rpm at crankshaft
Top speed: 163mph/263kmh (claimed, in street legal form)
Fueling: PGM-FI electronic fuel injection and engine management system, four throttle bodies w/two injectors per cylinder
Transmission: 6-speed, chain final drive
Electrics: 12v, electronic CDI ignition with two 8mm spark plugs per cylinder
Frame/wheelbase: Twin-spar beam frame in reinforced extruded aluminum/56.4in (1,433mm)
Suspension: 45mm Showa inverted telescopic forks front, single-sided aluminum swingarm with Showa monoshock rear
Brakes: Dual 12.2in (310mm) floating discs front, single 8.7in (220mm) disc rear
Tires: 130/70 x 16in front, 180/55 x 17in rear
Weight (dry): 489.5lb (222.5kg)
Seat height: 30.9in (785mm)
Fuel capacity: 4.6gal (17.3ltr)
Price then/now: $60,000/$75,000-$100,000 (est.)
Exactly 25 years ago, the most exotic and most expensive series production motorcycle yet produced by any Japanese manufacturer was launched in the marketplace as a 1992 model, embracing a level of technology that even today seems extreme — even compared to Honda’s recent limited-edition RC213V-S, a MotoGP racer-with-lights.
The Honda NR750, aka RC40, was the first — and so far the only — opportunity for even a few wealthy customers to experience the fruits of Honda’s high-profile focus on pursuing the holy grail of oval-piston engineering. It began as a rule-bending exercise, but by October 1991, when 16 select journalists were invited to sample the results, had been determined to offer significant mechanical advantages.
It’s strange that as an engineering-led company, Honda has so far failed to follow up on the NR750 by using this patented technology elsewhere in its product range — especially after Takeo Fukui, the NR oval-piston project leader, later became overall president of the Honda Motor Company. As such, it’s quite surprising he didn’t insist on introducing any of the bikes whose existence was hinted at by Honda insiders at the time, including a 250cc 8-valve single and 600cc 16-valve V-twin, each also sporting electronic fuel injection. Yet at a price of ¥5,000,000 — or $60,000 back then, roughly the equivalent of $100,000 today — the NR750 was only ever intended as a luxury purchase. It seems to be a technical dead end, a case of Honda flaunting its engineers’ cleverness in producing such a bike, not the advent of a new era in 4-stroke engineering.
The NR750 was an important step forward in two-wheeled performance, as it was the first Japanese sport bike to be fitted with fully mapped multipoint EFI, and the first from any country to feature upside-down forks, carbon-fiber bodywork, titanium anything, side-mounted radiators and exhausts under the seat. And in terms of styling, 25 years later, the NR750 street bike is still the most breathtakingly gorgeous, irresistibly seductive piece of Oriental two-wheeled splendor yet seen. The work of Honda’s design team headed by Mitsuyoshi Kohama, this not only rivalled the best that Italy had ever produced, but even inspired famed Italian designer Massimo Tamburini to copy it — as he later freely admitted.
Order the July/August 2017 issue of Motorcycle Classics to read more about the 1992 Honda NR750 RC40. Contact Customer Service at (800) 880-7567 or contact us by email.