company reverse engineered it as the basis for their first motorcycle. Nippon Gakki formed the Yamaha Motor Company in 1955 to build their copy of the RT 125 as the Yamaha YA-1, which was in production from 1955 to 1958. The YA-1 inherited design characteristics of RT 125 and, due to its thin body and chestnut brown tank, was affectionately nicknamed the . References RT 125 Motorcycles introduced in the 1930s Two-stroke motorcycles