Refining the Engine-a Top Priority

<< 1. Speeding Through the 1960s
<< 2. After a Decade, a Comeback to the Grand Prix
<< 3. Organizing the NR Block: Preparing for a Comeback
<< 4. Coming Back with a 4-Stroke Powerplant
<< 5. The Oval Piston: Heart of a New and Different Breed
<< 6. From Fantasy to Reality: Completion of the 0X Engine
<< 7. The Unconventional: Adopting a "Shrimp Shell" Frame
<< 8. The NR500s: A Humiliating Debut
<< 9. Refining the Engine-a Top Priority
<< 10. First Victory: The Suzuka 200-Kilometer Race
<< 11. The NS500, Honda's First 2-Stroke GP Machine
<< 12. Victory Again : After Fifteen Years
<< 13. Using Computer Analysis to Bring Honda Back, Stronger than Ever
<< 14. From the NR to Le Mans and Production Bikes
 


Having finished the 1979 season with disappointing results, the NR500s had two major problems that were considered unique to 4-stroke engines.

First, was the factor of extreme engine braking. When development began, the team viewed engine braking as an advantage, believing it would assist in overall control of the bike. On the contrary, the engine braking caused the rear wheel to hop. To counteract it, the team developed a back-torque limiter with a built-in, one-way clutch so that the wheel would spin when the force applied to the wheel exceeded a certain level. This methodology was later incorporated in the VF750F, making it the first production bike to be equipped with a back-torque limiter.

Acceleration was the second problem. It simply did not provide the necessary subtlety of control. The ability of the engine to generate ample low-end torque-a characteristic of 4-stroke engines-also made cornering control difficult, resulting in the loss of time. During the 1980 season the team experimented with throttle pulleys based on various shapes, but as yet there was no solution.

Weight was another area in need of attention. Although the first 0X engine was lighter than the average 2-stroke engine, weight gradually increased as durability improved. Before long, the engine had put on as much as 20 kg. The development team conducted an exhaustive review of materials, going to titanium and magnesium in order to achieve weight reduction. However, the new material combination was quickly copied by rival teams, leaving Honda with no advantage in that area.

The shrimp-shell frame, which had so greatly contributed to weight reduction, also had a drawback. Because of its cassette-type mounting structure, the engine had to be removed from the frame in order to perform maintenance. This made it difficult for the engineers to achieve optimal settings within the limited time allowed in the qualifying runs. Accordingly, the team decided to adopt a pipe frame to the machines, beginning in 1980. At the same time, the wheel size was changed to 18 inches.

Ultimately, the problem with the NR500 was that so many new technologies had been introduced that its potential for completion had been compromised. Realizing this, the NR Block prioritized problem areas, placing the top priority on refining the engine. This, they believed, was the most fundamental problem of the bike.

The new and greatly improved NR500s competed in an international race held in Italy. Although it was not a World GP race, Katayama was able to take the podium with a third-place finish. He also put up a good fight in the final round of the British World GP, held that August. The fifteenth bike to pass the finish line, his machine was the first NR500 to finish a GP race. Moreover, Katayama made a strong showing in the West German Grand Prix, finishing in twelfth place.

The 1980 season, however, closed with just two events in which Honda's NR500s made it to the final round. Still, the machines were making steady progress, so it was still possible to build a point total and finish the season in tenth place or higher. However, the reality was that they were still trailing the 2-stroke machines by 10 or more horsepower. Therefore, even if the NR500s could advance in the standings, they did not have what it took to win a GP race.

Yanase recalled a sentence in the plan document he had received in December 1977. It read, "Become the world champion within three years." He knew that 1981 would be the final year in that attempt, so there was not much time left.
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