Belgian Saroléa model 31R. This is a 500cc overhead valve Racing model from 1931.

This model was first released in 1930 as a faster version of the 24U and also had the upright cylinder. 1931 was the first year this model was released as a demolition derby motorcycle. Fewer than 200 units of this model were made in 1931. Racing continued until 1934, when it was replaced by the Monotube. The motorcycle has a Bosch magneto but also has a dynamo installation to power the lights. The motorcycle starts and runs well and has been ridden over many long distances. As an option, it has a 150 km/h speedometer driven by a gear in the front wheel. This model also had brake drums with cooling fins, as you can see in the photos.

Saroléa 500 31R with number 250607 was sold to Machand in Bouillon on April 23, 1931.