On paper, it’s a dream bike. How cool would it be to ride around on an incredibly light weight trials bike with a seat? In the real world, there are two problems: It’s not coming to America and, even if it did, its two-stroke wouldn’t be clean enough to meet US emissions.
Adding insult to injury are the Öhlins suspended Enduro 250i and 350i twins that also use the new motor. Ossa is light on info, but they do reveal that both the 250 and 350 weigh less than 220lbs.
Ossa’s direct-injection two-stroke is something we’ve never seen before. It uses two injectors, one in the crankcase and another in the combustion chamber, an ECU controlled power-valve, inhales through an air-box that lives inside the gas tank and expels spent gases through what might be the most complex exhaust ever produced. Direct injection is a big deal because it addresses the problem of unburnt fuel from the incoming intake charge escaping the cylinder through the exhaust port. With direct injection, fuel is added through the cylinder or cylinder head after the piston closes the exhaust port. The only thing in the intake tract is air.
At least, that’s how things would work in a perfect world. The crankcase injector in Ossa’s system pollutes the intake charge with fuel. Not as much as a carburetor would, or even a single injector, but enough to make things dirty. There’s another problem too: It still burns oil. A two-stroke needs either oil in its fuel or a separate oil injection system because the intake charge passes through the crankcase. Ossa isn’t saying how their motor is lubricated, but I’d bet that’s the job of the crankcase injector.