I thought that looked like Boris. I remember that when Fontana Dragcity was on it's way (1970 or so) out they would run shows on Sunday afternoons with a mixed bag of cars and bikes running. The announcer would say over the PA "here comes the dual engine Triumph with BIG BORIS AT THE HELM". On those Sundays we would ride our dirt bikes on a piece of property adjacent to the drag strip. Boris would be there with his kids in the morning before the show also riding their dirtbikes. He would help us fix our broken down bikes. Quite a mechanic and a real good dude