Correct me if I'm wrong, I think this is 1932, Jimmy Simpson fettling his 500 Norton International Model 30 - judging from the architecture and the Shell sign, in Sweden or Norway???
My multi-adjustable Laverda Jota bars (then fitted to my Guzzi) once came loose ridding the big dipper of Paddock Hill, Brands Hatch. While still on the move my index finger had to double up as a 10mm Allen key. BP