Yamaha RZ201

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Yamaha’s rotary motorcycle RZ201 was unveiled on the 19th Tokyo Motor Show in 1972 and surprised even many employees from the company, as most were totally unaware of this project.

 

The machine’s cycle characteristics were developed together with those of that other “bombshell”, the GL750 4-cylinder 2-stroke and the production machine TX750. The RZ201 had a wheelbase of 1.485 cm compared to 1.455 for the TX750. Weight was 220 kg against 230 kg respectively.
The “rotary” had the internal project code “YZ587” and the design sketches were approved by August 22, 1972. The Yamaha rotary engine utilized “CCR”/”OCR” (charge cooled rotor, but also oil-cooled rotor) The rotors had a radius of 83 mm and a diameter of 56 mm, resulting in a 660 cc displacement. Performance was 66 hp @ 6.000 rpm, comparable to the TX750’s 63 hp @ 6.500 rpm, (bore x stroke 80 x 74 mm).
As ignition Yamaha already used a full CDI system and most of the novel electrics used on the TX750 were also applied. An electric starter motor was also added.
A few RZ201’s were hand-made and according to some sources, 1 or 2 are still "hidden" in the factory to be discovered!

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Yamaha RZ201
Yamaha RZ201

 

Yamaha RZ201
Yamaha RZ201

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Yamaha RZ201
Yamaha RZ201

As I Indicated that there are many similarities between the cycle parts I think it is interesting to compare all 4 machines here. Let us take the "production" motorcycle first, as that machine functions as "donor" for the parts. The TX750 had the large diameter double cradle frame with a new front fork, front and rear fenders, alloy-rimmed wheels, cast-iron brake calipers and new, large instruments.

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The RZ201 was equipped with exactly the same components, it had a double disc brake (which the TX750 got for the European market). Even the fuel tank looks to be also taken from the TX750 parts bin.

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The GL750 also has the same lay-out (and the same parts. Main stand, side stand, it all looks very clever. The seat is silver, but probably the base was just stock TX750. I also believe that the fuel tank was a "chopped" TX750 item.

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It is going a bit far you might think but the engineers really did a lot of forward thinking in those days. The mighty Yamaha TZ700 racer which ruled the Daytona 200 miles for so many years had basically the same front fork, brake discs and calipers as the former 3 production and prototype bikes. It is a bit ironic that this art of very clever production is practically lost and on new machines it seems that every nut and bolt has to be re-invented again.......! But not with the Yamaha engineers in 1972/1973!

 

Yamaha TZ700
Yamaha TZ700
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