I have to admit that among all those wonderful bikes, I have a special like for this one.  Is it the genie of Rudi Kurth, the engineer (who was also known as a sidecar racer and innovator) or is it the riding style of Takazumi Katayama who gaved you shivers in the back only by watching?  I don't know, but this bike have a special place in my memory.  So here is its history:

In 1977, Takazumi Katayama is the first Japanese of the Motorcycle Road Racing history to be World Champion, riding a 350 Yamaha.  But not any Yamaha TZ, because it was a 3 cylinders made in Europe!

The first person to create a 3 cylinders based on a Yamaha engine is Rudi Kurth, a racing sidecarist known for his engineering talents.  Kurth start working on his project in 1975 and mount a 3 cylinders 500 Yamaha on his monocoque sidecar.  This engine is based on the 350 TZ and is, in fact, one half of a 350 'welded' on the left side of a complete 350 TZ and shortening the stroke from 64mm to 51.8mm to get the 499cc.  Here is the TZ and half.  His sidecar is quick but Rudi Kurth is better engineer than pilot and he does not often see the end of a race, unfortunately.  Two Dutch mechanics specialized in Yamaha, Ferry Brouwer and Jerry Van der Heiden, study the project of Rudi Kurth with Minoru Tanaka, Department Technical Chief of Yamaha NV, the European bureau of the Japanese bike manufacturer.  Tanaka and Brouwer are two friends since the time they were the mechanics of Phil Read and Bill Ivy.

In 1975, they decide to pay a visit to Rudi Kurth, in Switzerland.  Then, a bit later, a 500 3 cylinders is prepared in the workshop of Tom Van Heugten, the sidecar cross champion who is a bike dealer.  The engine develop roughly 90HP and it is mounted in a TZ350 frame, the third cylinder out of line on the left side of the bike.
In 1976, the Dutch pilot Kees Van der Kruys show right away the performances and reliability of the bike finishing 16th on the Belgian GP, on the fast track at Spa.  The 500 is only a start, Brouwer and Tanaka want to extend the project to a 350cc, and Kees Van der Kruys is assigned as test-pilot on the bike for the trials at a local race, end of July.

To bring this project from the National plan to the International one, the Grand Prix, a technical and financial help is needed.  It is Kunamotio San from Yamaha NV who start this European challenge.  Kent Anderson, the ex-world champion in 125cc is named chief of the project; Trevor Tilbury, young South-African mechanic join the team with Tanaka and Rudi Kurth.  Later, Tilbury will work for the Kenny Roberts team.
During the 1976 - 1977 winter, the work is hard in Holland, in Sweden and in Switzerland to be able to start the first Grand Prix as well prepared as possible.  The German firm Hoeckle is manufacturing the crankshaft at 120º, and Krober supply the ignition system.  This 350 3 cylinders is based on the 250cc TZ, with a third cylinder welded on its left side.

With a stroke X bore of 54 X 50.5 mm, the capacity is of 348cc and the power about 80HP @ 11,500 RPM, with a usable range from 8,500 to 12,500 RPM.  Both the Mikuni and Lectron carbs were tested, starting from the 34mm diameter.  At first, the engine is mounted in a standard TZD cycle giving a particular assymetry with a bump on the left - wher the third cylinder and the ignition plate seats - which often touch the ground in curves.
Even if it is possible to recenter the engine of few centimeters, the team prefer to build an entirely new cycle.  Niko Bakker and Spondon will make a new frame with a standard Yamaha fork on the front and a cantilever suspension.  At first, the wheels are Yamaha, to be replaced later by Campagnolo and Morris.
The weight is incredible, but in a wrong sens of the term; its 126Kgs are in the range of a 500 4 cylinders.  Kees Van der Kruys says: "In fact, our 500 3 cylinders weight only 115 Kgs because of an extensive use of titanium parts, which is not the case for the 350.  Kent Anderson does'nt agreed to use Titanium on the 350".

Overall, 5 engines were built for two bikes; one for Takazumi Katayama and the other for Giacomo Agostini, which guarantees the financial help of the Italian Importer, because Yamaha management refuse to help stating: "This is not a project Yamaha".  The two pilots have an identical machine, that each modify according to his tatse.  Agostini prefer the Marzocchi front fork and the gear shift on the right.
The first race for the bike was at Mettet track, in Belgium, the 24th of April.  Katayama will finish at an excellent 3rd place after having to stop to change the sparking plugs.

The first race on the World Championship is in Venezuela, but the team is not ready and prefer to wait 2 more weeks to be fine ready for the Austrian GP.  Takazumi Katayama falls during the trials and the race's day, the race was suspended after a collective crash, which has cost the life of he Swiss Hans Stadelman.
The next race is at Hockenheim, in Germany.  The long straight lines favor the 3 cylinders which lack maniability.  That day was the most glorious of the 3 cylinders:  Katayama and Agostini takes the two first places and Agostini break the circuit record of 2"5/10.  At Imola, Katayama finished third and Agostini had to retire.  Katayama is now heading the championship.  In France at the Paul Ricard circuit, Takazumi Katayama extend his lead by getting his second victory, beating Jon Eckerold and Bruno Kneubuhler, and again a new lap record.  Agostini finished at the 11th place and lost his will to pilot the 3 cylinders.
At Rijeka, Takazumi Katayama, with a broken shoulder bone, prefer to use the lighter and easier to drive bicylinder because the Yugoslavian track is very sinuous.  In Holland, at Assen, Katayama and Agostini retire with the bicylinders.  In Sweden, Takazumi Katayama is so daring that most of the pilots prefer to avoid him.
The victory in Finland assure the world crown for Takazumi Katayama.  The powerful 3 cylinders is clearly faster than its rivals at the road track of Imatra and everyone have been so impressed by the class and the control of Katayama.  It will  be the last victory for the 3 cylinders:  Takazumi Katayama does'nt go to Tchechoslovakia for a visa problem and at Silverstone, he prefer to concentrate only his efforts on the 250 category.

Takazumi Katayama race for the last time with the 3 cylinders in 1978 at Hilvarenbeek in Holland.  Then the 3 cylinders is transformed in a technical project of the Queen University of Belfast, and Ray Mac Cullogh drove it on the road circuits of North Ireland.  Later, Ferry Brouwer bought it back.

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