The first A10 I ever had was stolen. The guy was pulled by the police after a chase.
They said - we're talking 1973 or so - that it had been clocked at 103mph on the old Cambridge to Huntingdon road in the UK (A14 nowadays probably? - might have been then too). That had clip-ons etc and was a total eyesore, but that particular week it had nice cams and lumpy pistons, despite the iron head. 13 DTX where are you now? In which landfill, should I say?
Thing was, it did precisely 5 clattery miles after my getting it back - before a big end cap parted company with the rest of the rod and the motor was expensively wrecked.
Haven't ever tried anything like that with my current Flash - but it did run for 2 hours at a steady 75mph with me and one of my daughters on it a month or two back when things had conspired against us and we were running late for a good lunch. That seemed to be enough, but it didn't complain, didn't start doing the old heavy breathing routine, become incontinent, or any other bad thing. In fact, it just ran like a clock. Wonderful thing for its age, and in rather better shape than its rider - although we're both rough round the edges. If I wound it on, reckon it would run up to the mid-90s, but no intention of trying any time soon. 55-65mph is the comfort zone with its cooking engine I reckon. Haven't laid a spanner on it bar 5 oil changes and occasional rear chain adjustment in the last 5000 miles, which is more than I can say for one or two 4- and 2-wheeled moderns of my acquaintance. And my tatty 'B' is just as brilliant, just slower. Small Heath gets my vote if there is one . . . tremendous things. As one who spends a lot of time with his ample hind quarters slung over AMC twins and one or two other things as well, there's never any doubt which make to take when you know you have to get there. And back.