In the gritty General Electric town of Schenectady, New York, the Yankee Motorcycle Company held an open house in 1973 to show off its new Yankee Z offroad bike. Designed with enduro racing in mind, it was also road legal.
Although the bike was all-American, the engine’s origin was Spanish. The company was an importer of Ossa motorcycles and consulted with the factory over the concept. The Yankee Z’s lump was essentially made by slapping together the internals from a couple of Ossa 250cc two-stroke singles. A clever innovation was to use a splined shaft to mate them together, which meant it was a fairly easy modification to change the 360 degree firing order, where the pistons would move together, to a 180 degree configuration, where the pistons fired alternately, like most twins.
That wasn’t the only innovation. The Yankee Z was the first offroad motorcycle to feature a disc rear brake, and an oval swingarm.
Although superbly made, the bike was quite tall and heavy at 158kg. Production delays meant that by the time it was ready to roll, lighter, more reliable bikes were available end generally preferred by enduro riders. Fewer than 800 Yankee Z’s were manufactured. There’s one at the Barber Vintage Motorsports Museum, if you’re in the area..
If you want to know more about the bike’s technical specifications, this Cycle World review has plenty of details.