Wild Angels, Live...

Got this album for Christmas, obviously for the cover. Speaking of covers, it's what the band does with '50's and '60's rock standards. They're enthusiastic and sometimes hit the notes on the right beat.
But the cover is interesting, did they shoot this during an intermission on race day? Did they borrow these speedway bikes? Do they know what they're sitting on?
I couldn't get past the first paragraph of hyperbole in the liner notes, but I may try again later to see if it answers any of these questions...