Piet van Wijngaarden, winner of the first Dutch TT in Assen, 11th of July 1925. His motorcycle is a Norton Model 18. Note the raised handlebars, magdyno and cushion!
Simon: "I expect you may have noticed - it is fitted with a Binks Mouse trap carburettor. A few mid twenties Model 18s are listed in the records as being fitted with these instead of the more usual B and B."