The 350 X10 is much nicer han the 500 version, which can feel rough apparently. And it has a multi-plate wet clutch! Very smooth in operation. 80 mph should be doable.
+ What roadster said! I also found the caliper pistons were seizing up on the 2nd hand one I had. On the later new one, these were also greased, and the pad retaining pins removed and greased, and the fusebox hole stopped up. On the first, 2nd hand, one, one of the relays had to be bodged up to make work with extra wiring because that part of the fusebox base where the socket was, was corroded.