Drikko, Far be it from me to dishonour any of Baza Roberts considerable achievements on motorcycles but I think you might have duff information regarding Barry's backward riding exploits. Barry completed three forward facing TTs aboard Laverda triples and his respective average race speeds were 93.68, 91.44 and 83.21mph. I would imagine that the lowest speed of 83mph was a wet race. Some individual laps will have been quicker, possibly around 100mph
I think it's pretty clear from these speeds that lapping at 91mph backwards wouldn't have been possible, in fact I doubt if the timing gear would even be operable on a stunt like that.
Barry may well have ridden a Laverda triple backwards at 91mph, which in itself is a quite a feat, but a lap of the TT course at 91mph sat backwards up on the fuel tank from a standing start? I don't think so... I hope I'm wrong about this .