peds don't have the kind of suspension (or frame strength) to do that kind of stuff
you would break them in half with a major jump
I'm sure you could find a crazy stunt rider who would do it...but the ped would be a twisted broken heap after a few tries
And Rog... 50cc bikes won't do no 90mph (even with gearbox's)... the Bonneville records for 50cc are mostly around 65 to 75 mph.
There are a few records faster than 75mph... but those are manufacturer team bikes that are one-off specials.. with engineers and technicians right there working on them.. and very expensive and fragile.
I think the record (Kriedler) is actually 128mph for 50cc
I will try to post a link to a wild bicycle stunt here in a minute if I can find it.