The development story of the 125 ccm Yamaha Factory machines is very interesting as it started out with very simple machines.
The first 125 cc "racer" was a "tuned" version of the standard YA1, the "Red Dragonfly" I have to search of course for pictures of the missing models, but they will be added later.
Here is a list with all the real "Works" machines and their codes:
(Please note that the YA1 was a simple "tuned" standard production machine, used for a "primitive" form of racing)
The first really built for racing bike was the Works Asama 125 cc racer for 1957. A very special story will be made of these very early machines. The picture is from the start at the actual Mount Asama race in 1957!
The Yamaha RA41 G.P. machine was the first works racer built to race on the European G.P. circuits. The prototype was called YX41, a single cylinder engine with 2 rotary valves, which was used during the mid '61/end '62 period.
The machine specifications also included the already famous Yamaha Autolube Sytem (you can see the pump on top of the crankcase). Even one of the two carburettors can be seen.
By the end of 1962 the RA55 replaced the RA41 (November 1962) shortly as it was more a testbed for the RD56 twin 250 ccm racer to come.
The 1963 racer was named the RA75. It had an 8-speed gearbox and was used quite extensively. It was still a single, breathing through 2 big Mikuni M34 carburettors (again 2 rotary valves).
Here are some details of the RA75
The RA97 arrived on the circuits by mid 1964, preceded by the experimental YX97 machine. This new twin cylinder bike had a bore/stroke of 44 x 41 mm, a dimension which Yamaha would abandon later but after much consideration re-used in 1972. The first “generation” of the RA97 was air-cooled.
The RA31 was followed by the Yamaha RA31A, ultimately with 44 PS at 17.300 rpm.
The Autolube pump drive was used to drive the tachometer.
The second lot of YZ623C racers arrived a few months later and were photographed here in front of the Amsterdam garage of my boss, Mr. Ishibashi. Imagine that today, parking works machines in a normal garage in the city!.