1992 Honda NR750: Oval Pistons and 8 Valves Per Cylinder

1992 Honda NR750

1992 Honda NR750
1992 Honda NR750

Back in 1992, Honda once again stunned the world with the release of their revolutionary NR750 motorcycle. Featuring a totally unique and innovative look, with its one-piece tank, integrated seat and tail unit, and single side swingarm, it was actually what lay hidden under the carbon-fiber reinforced bodywork that had the world’s motorcyclists so very interested.

Essentially a Honda 750cc V-4, similar in layout to Honda’s all-conquering Interceptor line of motorcycles, the Honda NR motorcycle had some incredible technology lurking inside the compact engine. For the first time on a production motorcycle, Honda used oval pistons.

Honda had flirted with the idea in Grand Prix racing in 1979 when two strokes ruled the world, but the team did not achieve great success.

Inside the Honda NR750’s engine, each of the pistons—which looked like two regular items attached as if they were Siamese twins—used eight valves and two connecting rods.

Each cylinder received fuel from two injectors, controlled by the most advanced fuel-injection system seen on a production motorcycle, the PGM-F1.

The burned gasses were then pushed out through twin exhaust ports into an 8-into-4-into-2-into-1-into-2 exhaust system, an engineering masterpiece that exited from under the tail of the motorcycle.

The Honda NR750 power output was rated at 125 horsepower, delivered at a simply incredible 15,000 rpm, giving a similar horsepower per-liter-ratio to Honda’s current Honda CBR1000RR.

Priced at over $60,000, Honda only produced about 200 motorcycles, and none were imported by Honda to the United States.

Fantastic to look at, mind-bending to comprehend, the Honda NR 750 once more proved Honda to be the most technically innovative motorcycle company in the world.

1992 Honda NR750 Specs

Engine: 750cc V-four, oval-piston

Horsepower: 125

Weight: 525 pounds