Described by the vendor as a "B204 Sport 350", this machine does not appear in the Triumph catalogue for 1930 or 1931.
Part of a collection of engines, motorcycles and memorabilia from the Italian Motorcycle Museum in Amsterdam auctioned by Hessinkís Veilingen,
Nijmegen - Nederland, June 2007.

Image courtesy Hessink.nl
Triumph 1930s Models