c1981 Yamaha YZ250 Motorcycle
Yamaha’s original dirt bike, the DT-1, heralded the beginning of an off road revolution and led to the development of the legendary YZ250 in 1974, based on the machine ridden by Gary Jones to victory in the 1971 National Championship. Southern Californian Don Jones built his son’s winning machine around DT-1 components but added his own frame design, along with bespoke engine cases and a CZ alloy tank; the bike was subsequently sent over to Japan to provide the blueprint for a new range of production bikes. The lightweight YZ series was initially produced alongside Yamaha’s more mainstream motocross model, the MX, before the two lines were merged in 1976 and proved almost unbeatable on dirt, taking no less than 15 off-road championships and 14 MX titles in North America. Yamaha released an all-new YZ250 in 1977, consisting of a lighter frame with additional travel and a more compact engine. A plastic fuel tank and steel swing-arm were the other major changes, the latter switched to alloy for 1978. Yamaha reworked the monoshock design for the 1980 YZ250G, with an all-new frame design with a single front downtube and a revamped engine with improved reed-valve induction technology. For many pundits the YZ250s of this period remain the most desirable of all, before the switch to a new liquid-cooled version in 1982.