Friday bike

JJS X4 500

This is a prototype with a 500cc s troke engine with 4 cylinders arranged in an 'X' formation.

I have very little information on this bike other than it was built by Polish firm JJS Design & GG Tech, who have a picture gallery here.
They also have some pices of video illustating the valving and crankshaft layout on YouTube, but as the descriptions are in Polish I don't really know what's going on.