From NS to NSR

How Honda’s V four powered NSR500 rewrote the GP bike blueprint…

1983 saw the Honda triple benefitting from both a new, all-alloy, chassis and the introduction of reed valves – the latter update allowing smoother fuel/airflow with no opportunity of the engine to blow the vital mixture back through the carburettors. This pair of revisions enhanced what was already a very good machine, but the retention of works rider Freddie Spencer had delivered the key ingredient to Honda’s return to GP racing.

The 1983 season would prove to be very much a two-horse race with Yamaha’s Kenny Roberts consistently sharing podiums with Honda’s Freddie Spencer. This pair were so close in levels of skill, ability and machine reliability that between them they’d amass 286 points by the end of the season. Spencer would win over Roberts by 144 to 142, with third place man Randy Mamola only scoring 89 points aboard his Suzuki RG500 with Robert’s team mate, Eddie Lawson, grabbing 78 points to come fourth.

Both teams had played to their respective strengths with Yamaha tending to dominate at the tracks that rewarded outright power and Honda tending to shine on the tighter, more technical, circuits. Honda had finally once again won the prestigious 500 title but it had taken an embarrassing fall via the oval-pistoned NR and a potentially humiliating climb down using the much-vilified two-stroke to do it. That said, The Honda Motor Corporation was back and was not about to hand back the winner’s laurels easily.

The move to two-strokes had cost Honda dear both financially and emotionally but, if the company was to continue winning, it had to move on from the NS500 triple. The bike had served the company well but its advantages over the bigger, heavier, faster fours was marginal and only really came into play at twistier, pedantic, tracks. There were profound issues in getting more power from the motor and any extra horses liberated came at the expense of a dramatic increase in vibration. That said, HRC (Honda Racing Corporation) would still go on making the triple for chosen, second tier, riders and also offer privateers a slightly less potent version known as the RS500, which would go on to power Frenchman Raymond Roche to third place in the world rankings in 1984.

Whilst sales of the triple to a selected few took a little of the sharp sting out of a winter’s R&D costs, HRC had bitten the bullet and joined the four-cylinder circus with the NSR500 yet, as might very well be expected, with Honda’s unique twist. Taking lessons learnt from the NR500 in terms of weight minimisation, the all-new V four Honda 500cc GP bike ran a single crank as opposed to the competition’s twin crank, paired, designs – immediately a substantial reduction in mass.

Once again, following its credo of mass centralisation the motor was configured at 90 degrees keeping it, and the bike, as short as possible. Following this doctrine to its supposed logical conclusion saw HRC’s boffins effectively rewrite a GP bike’s blue print by siting the fuel tank under the engine with the exhausts running above it. The logic was simple and obvious, yet the reality differed from the science – the bike simply didn’t handle the way its riders expected and had the uncanny ability to catch them out. Irrespective of what the computers said, the cold logic of the designer’s predictions or the expectations and hopes of senior management, the radical design proved to be a step too far.

Road-holding issues and a tendency for the engine to overheat doomed the concept to failure. Spencer could only manage 87 points by the end of the season, coming fourth in the championship. Eddie Lawson on a YZR500 Yamaha would win with Randy Mamola second on an NS500 triple he’d leased from HRC! Once more Honda had overreached itself and allowed theory and ambition to win over practicality and compromise – science for its own sake had beaten the company again.

Probably embarrassed and certainly chastened, there were already revisions going on as the radical NSR500’s engine was cooling down. Next year Honda would be tempering its aspirations with a healthy dollop of level-headedness in the hope of regaining that precious title.

By Steve Cooper.

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