Can assure you, then..
That 120+ on a Black Shadow was as 'unremarkable' a velocity, in all terms of say, "routine confidence that one is in full control"
--as, was it simply 'normal': to cruise some long (boring) highway at 85-90 mph, taking advantage of fact that the wind pressure on torso,
which just-balanced any downward force on the handlebars (because of the forward body angle to the short un-raised handlebars)
--was kinda like "power steering" er, "wind-cancellation" driving: Bonus.
Worked for me--no butterflies.
(But yes, sustained 120 mph cruising would place a strain on shoulders, in time. No-traffic a requisite, natch.
Wind-force is still a force, resisted by muscles.)
Ed: PS: My brief tenure with a '70 Riviera, a thinly-disguised, actually good handling! 5000# monster, suggests that you might have hit 125ish;
that is, on one event I saw >130 on clock; shut down for doubt about tires' (near-new) max speed rating..
Was probably getting ~ 4 mi/gallon, then.. what a gas hog it was, those 5000#s.
