[[Image:Yamaha-YD1.jpg | right| 200px| thumb|Yamaha YD1]] The '''Yamaha YD-1''' was a 250cc, [[ twin-cylinder]] , [[ 2-stroke]] , [[ streetbike]] produced by [[ Yamaha]] starting in 1957.
[[Yamaha]], the youngest of the "[[Big Four]]" [[:Category:Japanese motorcycles|Japanese motorcycle manufacturers]], didn't build its first two-wheeler until 1954, when it unveiled a copy of the [[DKW]] [[DKW RT125|RT125]],calling it the [[Yamaha YA-1|YA-1]]. This spidery [[motorcycle]] was a great success. It won handily the first cindertrack hillclimb ever held at Mount Asama, north of Tokyo, in both 125 and 250cc classes. It was a decisive moment for
==Inspired by Adler==
[[Image:1957 Yamaha YD-1.jpg|200px|thumb|left|1957 Yamaha YD-1]]
But Yamaha's competitors were not standing still, so in 1957 Yamaha launched a new 250cc model, this time based on the [[Adler]] [[Adler
MD250|MB250]]. The new bike's main difference was in its frame, which was a pressed steel copy of the German Adler's cradle frame. Maybe that wasn't such a good idea! The first racing versions of the 250 YD1, seen at Mount Asarna in 1957 and in the Catalina United States Grand Prix in 1958, went back to the original German cradle design.
==A Brilliant Dynasty==
Yamaha was a fast learner and, within a few years, its twin had cast off all traces of its origins and had given rise to a [[motorcycle]] dynasty. The first was the electric-start [[Yamaha YD2|YD2]]. Then came the first dedicated sports models, the [[Yamaha YDS1|YDS1]] and the [[Yamaha YDS2|YDS2]] (the first model exported to Europe). Yamaha competed in its first French GP at Clermont-Ferrand in 1961 and returned in 1965 with a succession of famous riders -Vesco, Read, Redman, Ivy, Saarinen, and Agostini.
[[Image:1967 Yamaha YD-1.jpg|200px|thumb|right|1967 Yamaha YD-1]]
The first known Yamaha motorcycle in the US was purchased in Japan by Sgt. First Class Charles Butler of the US Army and brought to this country after his tour of duty in October 1957.
*[[Yamaha YD-2]] upgraded the YD-1 in 1958 by introducing electric start.