Way, way off the mark. Kawasaki didn’t make a Ninja when I was the age of the young man in your photograph. Andy
Here @El Toro can we fuck @hyperdildo out of here he called me and tit marsh !! And he hasn't even a duc anymore
what gives this photo away as not being genuine 50's b&w apart from the over exagerated roll top white socks.
I'll hazard a guess at the oil feed to the rockers, it looks like the alloy cooler fins, doubt they were available back then.