Mine? A ''69, (I think....), Honda SS 50 with a much faster engine built for the German market, (53 mph on that baby with the wind behind me!!), closely followed by a '77 pre-L.C. RD 250.
Fell off both many times, mostly due to a combination of year-round riding in crap English weather and a student income that didn't run to tires with any tread on them......
