This website has been developed to document the history of Yamaha's earliest racing motorcycles, starting with the works 250cc racers; the 1957 models code named the YD-A and YD-B.
The YD racers were specifically developed to participate in the 2nd Mount Asama Highlands Volcano Race in 1957, the most prestigious race in Japan at that time. If successful, they would prove Yamaha's superiority amongst the hotly contested Japanese home market; Yamaha were indeed successful!
The site also follows the restoration of one of these unique factory racing machines, the very YD-A which Osamu Masuko rode to victory at Asama and documents it's fascinating and pioneering history, paving the way for the global Yamaha brand as we know them today.
Please note, this site is a "work in progress" and will be being edited and updated as time goes on. 
I have used several pictures from sources online, wherever possible I have listed picture credits at the bottom of the page, if I have missed a credit or you do not wish me to use your picture, please advise me.
The YD frame as modified for the 1958 Catalina GP with additional footpeg mountings. It can clearly be seen that the subsequent racing machines followed this original design before Yamaha utilised the Showa influenced disk valve engines to produce the RD56 in 1963, although this basic design was to stay in Yamaha service on their production TD1 models until TD1C was replaced in 1969. Drawing by Chip Hellie.
It did not take Yamaha very long to develop their early racing two strokes into World beaters. They began by testing themselves against foreign machines in the USA, first at the Catalina GP in 1958 then 3 years later in 1961 they returned to compete in the US Grand Prix at Daytona (YX24 250S machines), shortly followed by tackling the Isle of Man TT and World Championship Grand Prix's (RD48 & RA41) with some good finishes achieved, including Ito finishing 6th behind Honda's domination at the TT as well as several wins in the non-World Championship events such as the Singapore GP. 
1962 was a quiet year for Yamaha, with some major development of the race bikes undertaken as well as finding and training new riders. This proved successful with the new TD1 racing model taking the honors at the All-Japan GP at Suzuka in both the Novice and 350cc classes.
Early in 1963 Yamaha won in both the 250cc class (Fumio Ito) and the open class (Don Vesco) at Daytona on the new RD56 machine. Then the elusive first World GP win came for Fumio Ito at the Belgian GP, with Sunako gaining 2nd place.  At the end of 1963 Yamaha drafted in Phil Read for the following 1964 season. Phil won the 250cc World Championship, the first in a long line....   
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Picture & Information credits
I would like to credit and thank the following websites for the use of their photo's used on this website:-
Cycle News
Cycle World
Yamaha Motor
Ferry Brouwer
Phil Read
And special thanks must go to Sonny Angel and Chip Hellie ! 
I have listed other contributors on the relevant pages.
Thanks to you all. 
Please note:
This is a private, non-profit making website intended for info sharing, research and recreational use only.