Memorable MC: 1973 Yamaha Monoshock — Motorcycle USA

23 Апр 2015 | Author: | Комментарии к записи Memorable MC: 1973 Yamaha Monoshock — Motorcycle USA отключены

Memorable MC: 1973 Yamaha

In 2010, the idea of an off-road having two rear shocks, than one, is as radical as the of a monoshock was in 1971. This is the of how Yamaha was the first company to a Monoshock in Grand Prix It’s a lovely tale and true too.

The 1973 Monoshock a novel design a fascinating history.

Some of it directly to me from Roger one of the great riders in the history of motocross. Although we weren’t going on vacation together, I Roger quite well and him tremendously as much for his intelligence and as his magnificent riding ability. was closely involved with the of the monoshock and wrote to me in the Autumn of

Fortunately, I still have the

I was also heavily involved GP riders in Belgium and had extremely relations with Yamaha at its race headquarters in Amsterdam. I knew and worked with GP star John Banks who was what was, at the start of the season, considered to be the best bike in the 500cc class the Cheney BSA. This is how the fits together from all sides:

In the late 1960s and 1970s, one of the great characters of motocross was Lucien Tilkiens, an designer and manufacturer of industrial cleaning machinery and water devices and also a lecturer in engineering at the University of Liege. Mr. had been involved in motocross for years and was very popular the riders — always to lend a hand with troubles and give assistance in special parts.

In 1971 Mr. son, Guy, was racing a CZ and managed to crash the bike — almost in front of his Dad saw the accident in detail and instead of his son for falling off, he came to the that the

The monoshock design allowed the wheel to stay planted in the without side-swaying and caused fatigue on the rider.

rear had kicked so viciously because the being applied to it could not be dissipated in the frame. Mr. Tilkiens that the near vertical of the rear shock, which was practice at the time, prevented the from handling extreme Mr.

Tilkiens felt that if the were transmitted along the of the frame to the steering head, the would be much better to deal with it, particularly if the was intercepted by a damper en route.

the mechanical ability to translate his into metal, it was not long a frame was built housing a damper interposed between the arm and steering head. This the Monocross which Yamaha put into production.

Guy Tilkiens favorably on the chassis and all through the season, work progressed on the new Having all the right contacts, Mr was able to get truly expert and took his bike to the Mol circuit Suzuki factory riders DeCoster and Sylvain Geboers it.

Their response was enthusiastic and who had engineers from the Suzuki staying with him at the time, for Tilkiens to have a new Suzuki machine into which a unit could be built. there would be a direct between a known quantity which DeCoster was familiar, and the new

The single shock Suzuki was and once again the reports favorable. Mr Tilkiens became about selling the idea to the What happens next on whether you are standing on the Yamaha or the side of the fence.

This is Roger told me: “Suzuki Mr. Tamaki over to assist on the with us at the circuit of Mol where lives. The result was that we liked it and told Mr. Tamaki our about it. He insisted that was no reason that the Tilkiens would be better just of the monoshock and the direction in which the was working.

These were Mr. Tilkien’s arguments for accepting the single system.”

In the early 70’s, were typically their own pit so riders had to know the ins and outs of machines.

“Later, thinking it myself, I realized that Mr was right and that the better of the monoshock was not caused by the system or etc. but because of the 50% increased wheel travel compared to our machine and also because of the good craftsmanship of Mr. Tilkiens and his to adjust the damping characteristics of the

Yamaha saw the story differently.

At the Yamaha works rider, Sao was on a racing trip to Europe as of his reward for winning the all-Japan Cross championship. With him was Suzuki, a free thinking engineer with the brief of in touch with the latest in motocross. Mr. Suzuki was unhappy the suspension media then in use and so had than a little interest he saw Guy Tilkiens’ Suzuki, apparently any rear suspension.

He studied the at the meeting and then, with efficiency, things began to very quickly.

The next that Toshinori visited European headquarters in Amsterdam, he that the Tilkiens’ Suzuki very similar to a “secret” which Yamaha knew was tested in Japan. This might have gone had it not been for Yamaha Europe’s Director, Mr. Nagoka, who had issued a to his staff that an active must be made for new methods of since frames and suspension had very little since the 1950s.

A meeting was called on a Thursday in and by the next day, Lucien had been identified as the builder and of the frame. This was decades e-mail, or even fax machines, so sat at Telex machines feverishly out terse teleprinter messages Japan and Europe as the plan was

Yamaha’s 250 engine with its reed-valve layout was key to the Monoshock’s in 1973.

The result was that senior executives headed for bright and early the next This was no fact-finding mission but one real power. The team was of Messrs. Nackamura, Kuratomo and and, after some difficulty, they located the country house from Lucien Tilkiens operated his machinery business.

Mr. Kuratomo, fluent in French, conducted the and after several hours of discussion, it was realized that Mr would be amenable to an offer Yamaha.

Suzuki had been the system for two months and after a long period without any move, Tilkiens was, not becoming rather impatient. His was that although he was a trained and university lecturer, he could not mathematically what was happening on the track. Suzuki’s engineers at were far less interested in the opinions of the riders than in evidence of what the men in the saddle to be happening and these facts not forthcoming from the mathematical which was submitted to them.

Mr. Tilkiens could not prove his in theory turned out to be not too surprising. eventually protected the Monocross with a battery of 30 patents the chassis design, the damper and the method of attachment to the frame but no-one managed to prove in terms the effect the system had on

Small wonder then, Lucien Tilkiens had such an struggle.

Yamaha was very of its Monoshock machine and its top rider Andersson in 1973.

Both and Tilkiens exhibited considerable and although an initial letter of was drawn up between the two parties, it was that the Belgian should Suzuki again and allow a week for a reply. No reply from Suzuki but the next a Sunday, an equally high-powered from Honda Belgium at Tilkiens’ house and began hard negotiating. However, by time Lucien had an agreement if the Monocross did not go to Suzuki, then would have it and the Honda were politely told they were too late.

showed no further interest the allotted time and by the following Tilkiens had begun work on a Monoshock machine and a team was groomed in Japan to carry out development.

The facts after stage are well known but the monoshock’s importance to motocross has a cloud hanging over it. was Yamaha’s season, at least in the 250 — about that can be no doubt. The 250 Yamaha engine, its very efficient reed-valve was far and away the best powerplant of the and their number one rider, Andersson, was at his peak — and the best rider in the competition.

factors, far more than the resulted in success.

In an interview American motocross collector, Clark, who now owns the actual World Championship winning Hakan said: “The time I saw the monoshock was in February of It was at a very remote track in the near a small village in Belgium named As. The Japanese this place because the project was top secret and they very careful not to be seen.

Hakan Andersson and the Yamaha won the Wuustwezel round and eventually the in 1973.

“I was very skeptical the bike when I first saw it. testing it, my first impression was it felt very strange. It was harsh in the rear and the seat hitting me every time I over the bumps.

The rear had too much compression damping and was no rebound damping at all. I was surprised that my lap times about equal to my best lap on the two shock bike.

“The really wanted me to start the Prix season on the Monoshock but I felt it wasn’t ready They put no pressure on me and left the decision up to me as to what bike to For the first two GPs I used the standard

“It took about two months of nearly every day to get the compression and damping and also find the spring rate, preload and gas before I felt the bike was up to its The Yamaha engineers, and my friend and Eije Skarin, did a great job to out all the problems in the beginning.

“At the third of the GPs in Belgium, I felt the bike was We picked Belgium for the monoshock because the track at Wuustwezel was to the one we tested on for so many months. was a calculated and well thought out

The bike was working very that day and I was riding very too. I had just recovered the ‘flu that I had at the Italian Prix and I was feeling very and confident.

“When the day was all over I had won The bike performed excellent. was very happy and we decided to use the for the rest of the season.”

At the end of the season, the combination of Andersson’s riding, the excellent reed-valve and the long

Hakan Andersson championship winning Yamaha Monoshock

travel suspension gave the 250 title. How much the single played in the success is very

What was the most tangible of the monoshock system was that by the end of the season, every bike in the GP was obsolete. 1974 would the application of a whole new concept in design and the key element would be travel — not the monoshock.

Banks, who campaigned a conventional shock Cheney throughout the season, remembers how quickly the came about.

“We came from Carlsbad, where the GP was held in June, and the bike was I had just got a second equal and it was as as anything in the world. It handled good and it was quick enough the straight, then, before we it, it was all over. The bike was just — scrap!

You just had to long travel rear or it wasn’t worth starting. It was how quick things changed.”

Our to Terry Good —  – for this assistance with article.

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