These are sweet. One is water cooled and has a happy time look. The other looks very much like the four stokes people are building.
http://www.yesterdays.nl/1926-e206-p-1107.html
http://www.yesterdays.nl/1929-racer-p-1305.html
http://www.yesterdays.nl/1926-e206-p-1107.html
http://www.yesterdays.nl/1929-racer-p-1305.html