2nd Update from the comments: Konig Racer. Really interesting engine cinfiguration.

Second Update: I've got the smartest readers on the web!

Lawrence wrote in:

A documentary about motor-racer Kim Newcombe, who turned heads in the 70s on a König motorbike he developed and designed himself. He was killed racing in 1973 and posthumously came second in that year's World 500cc Grand Prix. The film mixes interviews and underdog triumph on the track scenes, with Super 8 footage of family life on the circuit, and poignant wife-of-maverick reflections from his widow Janeen. Love, Speed and Loss won best documentary at the 2007 Qantas TV Awards and Air NZ Screen Awards for best documentary, directing, and editing.
http://www.nzonscreen.com/title/love-speed-and-loss-2007


Also:
http://www.fasterandfaster.net/2010/01/love-speed-and-loss-remembering-kim.html

Thanks Again!  You guys are the best!

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Update from the comments:
Hi,
it is not a twin engine. It is a 4 cylinder engine. Originally a motorboat engine.
Cheers Uwe

I suspected that it might be but it was hard to be certain from the camera angle. thank you for clearing that up! Makes it all the more interesting!

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A liquid cooled opposed four cylinder with a gear driven, toothed belt rotary valve intake intake setup. Interesting stuff.