The movie is “The Wild One” and is based on an incident that happened in Hollister CA in 1947, and involved the Boozefighters Motorcycle Club. HA were founded in 1948 or 1953 depending on whose story you believe.
Actually they treed Angels Camp also, maybe the movie was based on Hollister but the locals here think it was based on Angels Camp, and some old timers, who were kids them, still remember it. And I know the movie was “The Wild One”, the s just slipped in there as a typo. Still wish I had one of those Triumph 500CC twins. Can’t buy them any more.
*And* the “infamous photo” was staged.
The BF’s still laugh about it.