
Designed and build by Ilmor Engineering, the 800cc machine was spotted testing at Silverstone by an amateur photographer, Deborah Harriman, who initially did not realise what she had got.
Ilmor is best known for building CART and F1 car engines.
This design is said to be a V-four, using pneumatic valves. (See www.ilmor.co.uk and www.motorcyclenews.com)