Dear readers, this will probably be a long series and I will add also larger pictures to this file when time permits. That will be informed on the Homepage.

Yamaha chose the DKW RT125 as guideline for their first motorcycle. This was not only a management decision but also an engineering instinct to take this model. The RT125 was one of the best motorcycles of its time and the Yamaha engineers learned a lot from its design. Within their limited possibilities the engineers made some subtle changes to the original bike. The painted parts were even hand-rubbed down by craftsmen from Nippon Gakki's piano division! The tuning-fork emblem on the fuel tank was executed in cloissonne and very expensive to make. The YA1 was produced at the rate of 300 per month and in the 3 years of its production reached a total of 11.088.

Yamaha's entry into the very competitive Japanese Motorcycle market was with this German DKW RT125 inspired model. The YA1 had a 123 cc two-stroke engine with 5,6 hp and had already a 4-speed gearbox, while the DKW had a 3-speeder. The weight was only 95 kg, tyre size was 2.75-19. Colour was a nice maroon with creme fueltank sidepanels. Later a slightly larger version with 127 cc was introduced, the YB1.

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Yamaha YA1, Feb. '55

The second machine was also German inspired, now from the DKW RT175, but the engineers got already more freedom in their design. The 175 cc engine developed 10,3 hp @ 5500 rpm, tyres were 3.00-19, length 2040 mm and weight was 118 kg. Colour was a reddish grey, nicknamed "Champs Elysees in the rain"! From the sketches you can see that the model evoluated from the original DKW design to the final YC1 which had much more flair.

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Yamaha YC1, Feb. '56

The Yamaha YD1 250 cc twin was a giant leap forward for the company. Yamaha studied the German Adler MB250 as also Honda did (they took the leading link front suspension). But Yamaha wanted more and the engineers got free hand from President Kawakami. Together with GK designers they created this motorcycle and only the crankcase construction remained as Adler influence. The machine measured 1935 mm long, wheelbase 1270 mm, weight 140 kg and the engine developed 14,5 hp @ 6.000 rpm. It had a 4-speed gearbox and tyres were 3.25 - 16, at that time a very popular dimension for this class of motorcycle. In July '57 a 260 cc version was added (tax-reason). On the bottom-r.h. picture you see President Kawakami trying out the first prototype of the YD1.

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Yamaha YD1, Apr. '57

Here are the only 2 YD1 "official" pictures that I have. The "beach" picture has been published in several Yamaha and other Japanese publications.

Yamaha YD1, April '57

Yamaha YD1, April '57

The successor of the YA1, the (you guessed it already!) YA2, appeared in November 1957. Its construction had not much to do with the YA1 anymore. It was a quick transformation from a DKW replica to a Yamaha original. Teh design with a pressed steel frame was easier and cheaper to produce than the old tubular design of the YA1. It also had a bootm link front suspension and a normal rear swinging arm. It was a slim motorcycle with a weight 0f 103.5 kg. Length was 1870 mm with a wheelbase of 1245 mm. The 123 cc engine developed 6.8 hp. The colour was reddish metallic silver with chrome tank panels. It was also the first Yamaha with an electric starter, The second picture from the top left shows the YA3, introduced in December 1959. Colour was now black and the toolboxes were protruding from the frame now. Yamaha received a Government Good Design Award for this motorcycle, which was also Yamaha's first volume model.

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Yamaha YA2, Nov. '57

Yamaha was now already a volume production brand and the second generation of the 250 cc model had to be more modern. It received a pressed steel frame, like the YA2. What you can see from the sketches is that because of the "volume" of the frame there is little space between the cylinders, but for the battery and other electrics there is enough space. Lower left is the production version of the YD2, which appeared in December 1958. Neatly in black with a chromed fueltank it also had a downtube to the crankcases. It measured 1900 mm long, the wheelbase was 1270 mm and weight was 140 kg. Reasonably light in comparison with its competitors. The engine developed 14,5 hp and the YD2 was the first Yamaha to be exported to the USA. It was also sold in Mexico (CKD manufacture) and in Europe 40 were sold to the Netherlands (and a few to France). The YD3 (lower right) was similar to the YD2, but slightly more luxurious with larger brakedrums, whitewall tyres, 17 hp (!) and it was the first Yamaha with the 3 tuning forks proudly on the fueltank. (You can "click" on YD2 and YD3 to see my bikes.

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Yamaha YD2, Feb. '59; YD3, Nov. '61

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Yamaha YA5, Apr. '61; YDS1, Jul. '59

On the left side you see above the YA5 from April 1961 and thereunder the YA6 Deluxe model from November 1962. This new 125 cc bike was very important for Yamaha. it followed the same design route as the YD range. The YA5 was 1870 mm long, on a 1250 mm wheelbase and had a short-stroke (56 x 50 mm ) engine producing 10 hp at 6.500 rpm. Leg-shields were popular accessories at that time. The YA5 had to carry Yamaha over the difficult period with the failures of the MF1 and SC1 until the newer generation models arrived.

The YDS1 arrived in July 1959. In 1957 the second Asama Volcano race was held on the newly opened Asama Automotive Testing Ground and this was the scene of a direct confrontation between the giant Honda and the upcoming Yamaha. Yamaha defeated Honda convincingly in both the 125 cc class and the 250 cc class. The 250 cc machine was Yamaha's YD-A/B works racer. 5 of these machines, further developed, were later sent to the Catalina G.P. in the USA in 1958, where Fumio Ito scored a sixth place. While transforming the YD2 into a more sedate roadster, Yamaha catered for the sporting set by introducing an entirely new sporting model which was a derivative of the Asama-Catalina racer, This was the YDS1, initially introduced as 250S, featuring a new tubular duplex cradle frame. it was a purposeful machine with such mecahnical elements as carburetors, battery, electrical equipment all exposed.

Overall length was1990 mm, wheelbase 1285 mm, weight 151 kg, with 3.00-18 tyres. The 2-stroke parallel twin had the same bore/stroke of 56 x 50 mm as the Asama B type racer for a total of 246 cc capacity, from which it produced 18 hp at 7.500 rpm and it was mated to the first Japanese 5-speed gearbox. Yamaha separated sports from utility, but they intended the YDS1 to be a versatile sportster and prepared conversion kits for dirt racing (like Asama and Catalina) and enduro type competition. An interesting side-note is that the company displayed a promising 125 cc prototype sportsmodel, called Sports 125, at the 1959 Tokyo Motor Show, featuring a six speed gearbox. But this machine did not go into production. The YDS1 and its 260 cc sister model YE1 were commercially successful, and led the the later RD series of sports roadsters.

The SC1 was Yamaha's entry into the scooter segment. At that time the most succesful brands were Mitsubishi with their "Silver Pigeon" scooter and Fuji heavy Industries with the "Rabbit". The SC1 had a 175 cc engine (10,3 hp) which drove the rear wheel through a torque converter and shaft drive, too complicated as it turned out to be. The body was full monocoque construction as well. Today, with the oils we have now, most probably the machine would have been a very good one. But the SC1 was ahead of its time, as so many other motorcycles were.......!

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Yamaha SC1, Mar. '60

The small picture 2# shows a scaled-down clay model with a saddle type seat. Today you see this on modern 50 cc scooters! Picture 3# is a full-size clay model and the other pictures show further development to the final model. The last sketch show the monocoque body panels.

The MF1 was Yamaha's answer to the rapidly growing Moped Market. Yamaha wanted to have a sportier design (like with the SC1 scooter) Front and rear suspension were made by a clever rubber torsion spring and rubber coil spring. The bike had a 3.5 hp electric start engine with a 3-speed gearbox. Length was 1685 mm, wheelbase 1130 mm and weight was 67 kg. On the pictures you see the mock-up model and finally with the Chief Designer Kenji Ekuan of G.K. Design. The technical details show the suspension parts as well.

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Yamaha MF1, Mar. '60

The YG1 was positioned between the failing MF1 and SC1 models and actually "rescued" Yamaha financially. It had been designed already a year earlier and the new President, Mr. Koike, grabbed it and brought it into production. It was an instant success worldwide and sold in the thousands for many years. The second picture shows the YG1D from Apr. '64 which was the first "Autolube" model. Length was 1815 mm, wheelbase 1145 nn, weight 70 kg and the 73 cc rotary valve engine developed a healthy 6.5 hp @ 7000 rpm. It had a 4-speed gearbox. Picture 3 is the YF1, a 50 cc version of the YG1 (Apr. '64), with the leading link forks of the old MF1.

Yamaha YG1, Mar. '63

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Next (4) is the YF1A (Jun. '65), the YF1 got new telescopic forks. (5) is the YJ1 (60 cc) of May '64 and (6) the YJ2 (Jun. '65) where it got also telescopic forks and "Autolube". (7) is the H1 (May '65) A 90 cc model joined the family. With a different tankshape from the YG1 it was more similar with the YA6 (125 cc) and YDS (250 cc). (8) is the YK80 (Sep. '66) A direct evolution of the YG series with H1 type tank. (9) is the YP1 of Mar. '65, a sporty model with the same type "T" backbone-frame. The 50 cc engine had 6 hp and the semi upswept exhaust, sporty shockabsorbers and other details made it a nice little machine. Picture (10) is the YGS1, a very sporty variant in the series with a very healthy 8,8 hp engine.

With project "YX07" Yamaha departed from the YG frames with the so-called "7-type" frame. This is still produced in bikes like the YB series 40 years later! (1) Final mock-up (l.h. 2) with single rotary valve engine. (3) is a YX07-1 with a 90 cc twin cylinder engine (H1), this idea was cancelled as it was not "commuting". (4) r.h. upper is the first production bike, the H3 of Aug. '66 with sporty fueltank, 86 cc engine with 8 hp @ 7000 rpm and 4-speed gearbox. (5) is the F5 of Dec. '67 with nice long and slim chrome sided tank. There was also a 60 cc version. (6) is the G5 of May '68 as last 80 cc model with a larger chrome area on the tank to distinguish it from the smaller bikes.

Yamaha YX07-2, Jun. '65

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