The MotoGP spannerman’s tale: part 1


Stuart Shenton was a race mechanic when he was still at school. Jobs with Kork Ballington, Freddie Spencer, Wayne Gardner, Kevin Schwantz, Anthony Gobert and Loris Capirossi followed, as did world titles with Kawasaki, Honda and Suzuki. He’s a man with plenty of tales to tell…

Stuart Shenton

Shenton (right) with Wayne Gardner and fellow HRC mechanic Dave ‘Radar’ Cullen during 1988 testing

Shenton archive

Stuart Shenton’s first experiences as a teenage factory race mechanic quickly taught him that racing isn’t all about spinning spanners and twisting throttles.

In 1975, Kawasaki unleashed its water-cooled KR750 on the F750 World Championship, originally created for bikes with streetbike engines. Only one problem, the factory hadn’t built enough bikes for homologation.

“We had a lot of riders at the Ontario F750 round – Mick Grant, Miguel Duhamel, Art Baumann, Gregg Hansford, Murray Sayle and so on – so we had 17 or 18 bikes, but we needed 24 for homologation,” Shenton recalls. “So we put all the bikes in one place and the FIM guy was brought along to look at them. We told him the other bikes were somewhere else, so why don’t we have lunch on the way to see them? By the time lunch was finished, the bikes had been moved and were duly shown to the FIM guy, all over again. It was all a bit of smoke and mirrors.”

That’s what Kawasaki was prepared to do to win, but it’s nothing compared to the skulduggery attempted by a rival brand three years later. In March 1978 the Kawasaki crew arrived in Caracas for the season-opening Venezuelan Grand Prix with new signing Kork Ballington and their brilliant new KR250 and KR350 twins. At least, Shenton thought the bikes had arrived.

“We went to the customs warehouse with our carnets, only to be told, ‘very sorry, your motorcycles aren’t here. We don’t think they ever arrived’. We made phone calls, sent telexes and, yes, the bikes had been on the plane over. We had a local guide from Kawasaki who was driving us around. He said if they’re not here, someone’s taken them and I know who.

“We got back in his car, the guy reached under the seat, pulled out a gun, checked it was loaded, put it on the dash and said, let’s go and get the bikes. We said, is there going to be any shooting? He said, well, there might be.

“On the first day they said sweep the workshop floor. The American said, I’m not here to do that kind of stuff, so he was put on a plane home and I stayed.”

“It was a bit like a film scene. He drove us down the back streets of Caracas and into this compound with the horn going, waving the gun out of the window. I guess we were lucky he had more front than the others. This was the yard of Ippolitos, the local Yamaha importers, and sure enough, hidden away in a corner were our crates…”

Once Ballington got his bikes back he dominated the 250 and 350 classes, winning a back-to-back title double in 1978 and 1979. That’s four world titles and 22 GP wins in two years, not bad going.

Shenton came to racing by way of his father Stan, who had been a Spitfire mechanic during the Second World War and nurtured his love of racing on RAF airfields. “Dad used to race bikes around the runways and get into trouble. He was on the same base as Colin Chapman [founder of Lotus Cars].”

After the war Shenton senior ran the Boyers dealership in Kent, selling and racing Triumph Bonnies and Tridents. By the time Kawasaki asked him to run its first UK racing operation, Shenton junior was already working for the team in his school holidays. Next he started an engineering degree, but his studies were soon overtaken by racing duties.

Stuart Shenton

Shenton (left) and Kork Ballington (right) with Kawasaki’s KR500

Shenton archive

“The first thing Kawasaki gave dad was a standard H2-R [the precursor to the KR750], which was a dreadful piece of kit. It had this huge magnesium rear drum brake that was fine until it got hot, when all the spokes would fall out.”

After several seasons working on H2-Rs and KR750s, Shenton switched to the 250/350 tandem twins.

“We got the first 250s in 1976 but couldn’t race them because they were so bad. The engines destroyed themselves and vibrated so badly they’d literally break the frame in half. The factory had built them without anyone knowing, sent them over in crates and told us, oh, by the way, next year you’re going to have a 250 too.

“They were so bad – horsepower-wise, reliability-wise – that they were a wake-up call for Kawasaki who then built the fabulous bikes that Kork used.”

The problem was the fore-and-aft cylinders firing 180 degrees apart which caused disastrous vibration. Later versions fired both cylinders together, with counterweights to cancel primary inertia forces.

In late 1977 Kawasaki summoned Shenton junior to Japan; they had big plans for him. “I was in Kobe for three months, lived in a working mens’ hostel, which cost a dollar a day, slept on the floor and ate a bowl of rice every morning.

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“Kawasaki said they wanted to train me, so I had a month in the drawing office, a month in the workshop and a month on the dyno. I was very lucky, it was a fantastic opportunity.

“There was me and a guy from America. On the first day they said there’s 40 wheels and there’s 40 tyres, so put those 40 tyres on those 40 wheels and when you’ve done that, sweep the workshop floor. The American said, I’m not here to do that kind of stuff, so he was put on a plane home and I stayed.

“I enjoyed it. It gave me a strong grounding of understanding the Japanese, which stood me in very good stead. Then there was another big surprise: oh, by the way we’ve also built a 350, which they hadn’t even told us about. Kawasaki hit the ground running with these bikes in 1978. They’d done a complete redesign and got on top of the twin firing order.”

“The new chassis was designed by Kinuo ‘Cowboy’ Hiramatsu, who also designed the 250/350 frame and was later headhunted by HRC. They called him Cowboy because he used to walk around in a pair of way-too-big racing boots that someone had given him.

“Kawasaki got there by perseverance and by Japanese attention to detail. The Japanese will take an idea and develop it to death, where perhaps others run out of money or ideas.”

He said to Fukui, ‘are you stupid? Did you pay attention at school? Because you don’t know what you’re talking about!’

In 1980 the factory took the next step and built a 500, the square-four KR500 that was either a doubled-up KR250 or a Suzuki RG500 rip-off, depending on which way you looked at it.

Ballington rode the 250 and 500 in 1980, and would’ve completed a 250 hat-trick if he hadn’t fallen dangerously ill with a gangrenous perforated gut, the result of an earlier injury.

“Kork was one of the first professionals. He kept himself fit and he was super smooth, which made him untouchable on road circuits like Imatra and the old Brno and Spa. Kork thought a lot about how to go quicker, focusing on being faster through the bits that weren’t so dangerous.”

Stuart Shenton

After his move to HRC Shenton works on Takazumi Katayama’s NS500 triple

Shenton archive

If the racing was dangerous, the Sunday nights were also quite scary.

“I remember being in a rentacar with Dozy and a few other guys from Kenny Robertsteam. It was Sunday night in Misano and Kenny jumped out of a first-floor restaurant window onto the roof of our car, collapsing the roof down on top of us. Then he insisted we drive through the town with him sitting there.”

The KR500 promised much but never quite delivered. Hiramatsu tried to push things forward with a monocoque frame.

“The 500 was way overweight and probably way too stiff, which we didn’t realise at the time; though we did have an inkling about stiffness – we were always worried that if Kork crashed, the bike would take out half a mile of Armco! The chassis was unusual; you could make a quick trail adjustment by changing the front axle position in eccentrics in the front forks, or you could unbolt the steering head and bolt in a different one to lengthen the bike or change the angle.”

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Sadly, Hiramatsu’s creation only proved that old racing maxim: evolution is better than revolution. Ballington scored two third-place finishes with the bike in 1981 and then the project was dropped.

Shenton was immediately signed by HRC, to work on the game-changing NS500 triple, with Japanese rider Takazumi Katayama.

“That was a real eye-opener, going from Kawasaki’s very small team to HRC. At the first test I did with Honda there were about 70 people there. You could see they only had one objective: to annihilate everyone. They’d just had the four-stroke NR500, which had failed miserably, then they’d built this unconventional three-cylinder bike. From Mr Honda’s point of view, it was a case of you better get it right this time!”

Soichiro Honda was loved by many who worked for him, but he wasn’t always an avuncular boss.

“In 1985 Mr Honda came to Jarama and we were told he would be visiting Katayama’s garage. We were told what to do and where to be, then we stood there waiting. Mr Honda arrived and laid into Takeo Fukui, who ran HRC and later went on to be Honda president. I asked one of the Japanese what he was saying. He said to Fukui, ‘are you stupid? Did you pay attention at school? Because you don’t know what you’re talking about!’ He said, right, you’ve built these bikes with reed valves, now bring me a reed valve. Then he lectured the engineers about how he thought the reed valve should be.”

Next week: guiding Freddie Spencer and Kevin Schwantz to world title glory and working with arguably the greatest rider of all time, who never even won a GP