RACERS - Racers - Vol.55 Honda NR500 Part.2 (Sanei Mook)

Looking back now on the racing machine of yesteryear - the NR500 with its oval piston started running and kept running.

Honda NR Challenge

Adventures of NR

Part 2 Technical Review

Elemental technology of the NR500 that achieved output of over 250 horsepower per liter 40 years ago

★ Pages 14-15

This document, titled ``NR Road Race Project PHASE-1 Promotion Plan,'' is a strategy book and organizational blueprint that shows in detail how to develop and operate the NR500. The person who created it was Takeo Fukui, who later became Honda's sixth president, and it is said that he was notified within the project in November 1978, when the design of the monocoque frame (commonly known as the "shrimp shell" frame) began. Although it is an internal document that is classified as completely confidential, the Racers editorial department has reproduced it through this interview.

★Page 24-25

At Honda, he called his engine with an oval piston (or more accurately, an oblong piston) the "UFO." With DOHC's 32 valves (8 valves per cylinder), his 500cc V-4 engine can rev over 20,000 RPM and 130 rpm to compete with his 2-stroke rivals such as Yamaha and his Suzuki. You have to squeeze out more than the horsepower. Although it was possible in calculations, various difficulties befell his NR project when he started manufacturing it. By the way, this photo is of his cylinder head on his NR500 (provided by Honda).

★ Pages 32-33

Let's take a closer look at his past NR500 engines. First of all, the engine called ``0X'' was installed in the first machine, development code: NR1, which rider Keisuke Katayama drove at the British GP in 1979. The page introduces the design drawings obtained from his Honda company. Its V bank is 100°. At the time, a bevel angle of 100° was still required to accommodate the NR-specific carburetor unit, which was a combination of the downdraft type for the front bank and the side draft type for the rear bank, while ensuring an appropriate intake passage.