MotoGP tech development: when imitation is the sincerest form of flattery

MotoGP

At the end of last season Honda’s RC213V wore Ducati-style diffusers and seat aero, but this wasn’t the first time Honda has flattered its rivals with imitation

Freddie Spencer on Honda NS500

Freddie Spencer aboard Honda’s first two-stroke 500cc GP bike, the NS500, created to beat the Kawasaki, Suzuki and Yamaha two-strokes

Honda

Mat Oxley

Honda has just completed its worst grand prix season since it raced the fabulous but flawed NR500 four-stroke in 1981. The company didn’t score a single MotoGP victory during 2022, but even so, the RC213V did much better than the NR.

During four on-and-off seasons, from 1979 to 1981, the oval, piston, 32-valve, 22,000rpm NR didn’t only fail to score any GP victories or podiums it also failed to score a single world championship point.

How the hell did that happen?

Honda has been a four-stroke company ever since founder Soichiro Honda decided his first motorcycle, powered by a two-stroke engine, was too dirty and smelly. Meanwhile his main Japanese rivals – Kawasaki, Suzuki and Yamaha – all made their names racing and selling two-strokes, before switching to four-strokes as global environmental legislation intensified.

Honda’s engineers were trying to go to Mars while Kawasaki, Suzuki and Yamaha were going to the moon

Honda enjoyed great success racing four-strokes in the 1960s but as the two-strokes got faster and faster there was no way that four-strokes could compete with them because a two-stroke engine fires once every revolution while a four-stroke fires every other revolution. So Honda quit GP racing at the end of 1967 and stayed out for more than a decade.

Finally, due to demand from its importers around the world, the company returned to GP racing in 1979 to promote its latest high-performance road bikes. But still it refused to race two-strokes, so it created the four-stroke NR500. The theory went that the NR would defeat the two-strokes, which produced peak power at around 11,000rpm, by revving to 22,000rpm.

Although it never scored a GP point the NR is one of the greatest engineering tales of bike-racing history. Honda probably spent more money on it than any of its other race bikes, but its engineers were trying to go to Mars, while Kawasaki, Suzuki and Yamaha were going to the moon.

The NR500 was the polar opposite of today’s MotoGP bikes – inspired, radical, blue-sky thinking versus ultra-restrictive technical rules.

1970 Honda NR500

The first NR500 of 1979, with monocoque chassis and pannier radiators wrapped around its 32-valve V4 engine

Honda

Anything went with the NR. It used oval pistons (about 80mm long and 30mm wide), with eight valves (four inlet, four exhaust) and two conrods per cylinder, camshaft gear trains and an innovative slipper clutch. Designer Shoichiro Irimajiri’s concept was to keep to the four-cylinder maximum but make the engine work more like a V8. Honda’s initial idea was to use lots of ceramics and cool the hard-working engine with liquid nitrogen.

The original aluminium monocoque frame, soon replaced by a conventional tubular-steel, was equipped with smaller 16in wheels, to lower the bike for reduced drag, with the 16in-tyres made by Michelin specifically for the NR. Later versions sometimes used carbon brakes, a decade before they were successfully used by other premier-class factories.

However, the engine was fragile. While today’s MotoGP riders are allowed seven engines per season the NR got through so many engines that Honda sometimes secretly rented workshops near each GP venue, so while one team of engineers worked on the bikes at the track during the day, another team worked nights, rebuilding engines for the next day.

“When we went to Silverstone for the first race [the 1979 British GP] we’d take the engines out at the end of practice and we’d still be there at two in the morning grinding in valves for the next day,” remembers mechanics Nigel Everett. “It took 60 man-hours to fully build an engine. A cylinder head took 20 hours, just to do the shimming and grind in the valves, which were like 5p pieces.

“The NR had the first slipper clutch too, because it was unrideable without one. You had six different clutch spring colours and to get the strength you wanted you could use about a hundred different combinations according to a chart.”

Soichiro Honda with Motorcycle Grand Prix Honda mechanics at Brands Hatch in 1980

Soichiro Honda with NR500 mechanics during the 1979 British GP at Silverstone, where the bike made a disastrous debut

Bernard Cahier/Getty Images

“I always thought it would work; it was so trick. The couplings for the water system were self-sealing, so there was no draining water or anything. And the engine had nylon runners on it, so it just slid into the monocoque frame. You just docked them together.

“The noise limit was the problem. When they brought it down to the limit it lost a lot of power but when they ran it with straight pipes on the dyno it gave good power.”

The NR made a disastrous debut at Silverstone, where riders Mick Grant and Takazumi Katayama started from the back of the grid. Grant crashed at the very first corner, after oil spewed onto his rear tyre. Katayama stopped two laps later, also with an oil leak. To make matters worse, Honda-san had flown in from Japan to watch his company make its return to GP racing.

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The NR did nearly make it into the points at Assen in 1981, until the ignition cruelly failed on the final lap. By this time Honda was getting desperate, even taking some NR parts to be blessed at a Buddhist temple in Japan, in the hope of some divine intervention.

“I was having a lot of long talks with Iri-san, [Irimajiri],” recalls Gerald Davison, boss of HIRCO (Honda International Racing Company), which was established to run the NR project. “Half joking, I told him he should send the NR people to a temple and tell them to really reflect on what they’re trying to do. The very next day he did just that! A fleet of minibuses took 40 of us to a Buddhist temple. We also took along some bits of the bikes that would receive blessings. So we arrived at this beautiful place, up a forest-clad mountain, with dancing girls and music. It was all pretty spectacular.”

However, divine intervention came there none. By now some Honda people already knew their goal of trying to beat the dominant two-strokes with a four-stroke was hopeless. These included engineer Youichi Oguma, a former racer and road tester, who had played an important part in the development of the CB750, the original superbike.

“I told the bosses that the NR was impossible,” says Oguma, who managed Honda’s GP effort from 1987 to 1993. “I said we must use our two-stroke motocross technology. This was fantastic technology, because we had dominated domestic titles and world championships with our two-strokes. Now we could use this knowledge for road-race bikes, it was very convenient.”

1980 Honda NR500

The 1980 NR500, with conventional tubular steel frame, made by British chassis designer Ron Williams.

Honda

In the summer of 1981 Oguma travelled to Europe on a fact-finding mission, examining rival machines at scrutineering and then around the track, taking photos and split times at different parts of circuits. His report dropped onto his bosses’ desk back in Japan “like a bombshell” and Honda was ready to swallow its pride like never before or since.

The man given the huge responsibility of regaining company pride after the NR – which was eventually nicknamed the Never Ready by the media – was Shinichi Miyakoshi, who had worked on Honda’s 1960s GP bikes and created the marque’s first two-stroke racers, the RC motocrossers, which took Honda’s first motocross world title in ’79.

Honda had no doubt who it wanted to lead its first two-stroke GP adventure: American superbike rider Freddie Spencer, who had only ridden in two GPs and finished neither of them (not his fault).

At the 1981 British GP, Spencer’s talent had the NR up to fifth place, before the engine expired.

According to legend, the final decision to use a 3-cylinder engine was taken during an enthusiastic drinking session

“The NR was actually fun because it was so unique,” remembers Spencer. “It didn’t feel like a four-stroke. The motor had such a short stroke that it needed so many more rpm to get the horsepower. Its biggest problem was no torque and not much mid-range, though top speed wasn’t so bad compared to the two-strokes. Because it had no torque you had to use a lot of corner speed, so it was always tucking the front – If a bike lacks power, you’ve got to make it up some place else.’

Miyakoshi’s new engine wasn’t as wild as the NR500, but it was still very different from other bikes on 500cc GP grids, because Honda still wanted to do things differently, so he flew to the USA to convince Spencer and his tuner Erv Kanemoto that his creation would be a winner.

“Erv and I were sitting in a room with this big box on the conference table,” Spencer recalls. “We were wondering what was in the box when Miyakoshi comes in and opens it up. Inside there’s this three-cylinder motor. You should’ve seen the look on Erv’s face! It wasn’t anything like what the other factories were racing, then Miyakoshi explained his theory about how the NS was lighter, narrower and so on.’

The first task in building any race bike is deciding the basic engine configuration, because that’s the heart of the machine. Miyakoshi sketched a square-four, a V4 and a V3. According to legend, the final decision was taken during an enthusiastic drinking session involving Miyakoshi and Oguma. Both men had the same idea, the three-cylinder made the most sense.

Honda NR500 with carbon fibre frame

The final NR500, with full carbon-fibre frame. The bike was exhibited at the 1983 Tokyo motorcycle show and never raced.

Oxley

“All the other engines were too big, too heavy or too complex,” reckons Oguma who, during his European visit, had noticed how twin-cylinder 350cc GP bikes were very nearly as fast as the 500 fours at some tracks.

The NS500 was arguably the first modern MotoGP bike, because it prioritised overall performance over outright engine performance. Its four-cylinder rivals – Kawasaki’s KR500, Suzuki’s RG500 and Yamaha’s 0W61 – were fast but unwieldy, their chassis and tyres overpowered by their engines. Miyakoshi and Oguma acknowledged that corners are as important as the straights. More so, in fact.

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Miyakoshi’s triple also used reed-valve induction, the technology borrowed from Honda’s motocrossers, while Kawasaki, Suzuki and Yamaha all used rotary-valve induction to feed their fours. Once again, this was all-round useability trumping peak performance.

Spencer still remembers arriving for his first proper test on the NS500, in Brazil, just weeks before the 1982 season-opening Argentine GP.

“That was the first time I met Marco [Lucchinelli, who had won the 1981 500cc world title with Suzuki, then defected to Honda]. I walked into the hotel and Marco’s by the pool, with two Brazilian girls… Man, there’s the world champion!”

The NS500 was immediately competitive, battling for the win its very first race at Buenos Aires, where Spencer finished third, right behind Yamaha rivals ‘King’ Kenny Roberts and Barry Sheene.

Six races later Spencer rode the NS500 to its first victory, at Spa-Francorchamps. There’s no doubt the NS didn’t win races just because it was a well-designed GP bike. Spencer’s riding genius played a huge part, his magical speed assisted by his ability to assess the smallest set-up changes in a few laps, a very useful skill when developing a brand-new motorcycle.

1983 Honda NS500 of Freddie Spencer

Spencer’s 1983 title-winning NS500, with aluminium frame – the bike was much more manoeuvrable than its four-cylinder rivals

Honda

“Freddie had a tremendous amount of natural ability, he rode by feel and instinct,” explains Kanemoto. “He did no weight training and not much testing, though when he did test he was remarkable.

“When most riders go tyre testing they make a lot of laps to get up to speed to feel and understand the tyre, then they start pushing. Freddie would push from the first lap on a tyre that no one had run before. You’d see these giant slides and he’d just rely on himself to get out of it. That was his strong point.”

Spencer finished 1982 third overall, behind champion Franco Uncini (Suzuki) and Graeme Crosby (Yamaha), and the following year played his part in arguably the greatest MotoGP championship duel in history.

He lined up alongside Roberts, who had won the 1978, 1979 and 1980 500cc titles on inline-four Yamahas, then suffered greatly when Yamaha engineers lost their way, creating three very different and badly behaved machines over three consecutive seasons: the rotary-induction square-four 0W54 of 1981, the rotary-induction V4 0W61 of 1982, with horizontal, sideways-mounted rear shock (the worst GP bike Yamaha ever made, according to Roberts’ crew chief Kel Carruthers) and the rotary-valve V4 0W70 of 1983.

The two Americans each won six races during the 12-round 1983 500cc world championship, Spencer and the NS500 taking the title at the final round by just two points.

Their battle for the crown was more like a war and climaxed with death threats at the Imola finale. But that’s a story for another day…

Next week: How Honda is trying to dig its RC213V out of a hole for the 2023 MotoGP championship