For some reason I have always had an interest in all-terrain vehicles, like four wheel drives, 6x6 or 8x8 trucks etc. I also wondered how feasible two wheel drive on a motorcycle would be, considering it would have to be a fairly complex mechanism to build.
And then I saw the Rokon Trail-Breaker in a museum which has exactly that: two wheel drive using a fairly complex mechanism. The original design is invented around 1958 and the model shown here is the 1969 version. Rokon still builds Trail-Breakers but in a modernised form.
The motorcycle has large balloon tires which can be filled with fuel or drinking water for long trips using the tires as containers. When filled with air, the motorcycle will actually float to help in river crossings. It's capable of climbing 60% grades with the two driven wheels.
This Lego model has a fully functional drive train between the one cylinder engine, through a rubber belt (a Lego rubber band) to the chains and drive axles that transfer power to the wheels. The tank, saddle, engine and transmission parts as well as racks to transport loads are all detailed in the model, along with the tell-tale Trail-Breaker logo on the tank. The model is like the fusion between a Technic set and a Creator set, with working technical details and detailing for realism.