Just been reading about this, 1962 Bert Fruin 200cc four cylinder two-stroke, recently restored by Noisy Toys whose website is worth a browse ...
This Bert Fruin masterpiece is one of the 200cc kit form engines marketed for 1961 but due to the complex nature of the design and cost only two were ever made. The four cylinder engine was originally sold as a set of unmachined castings with two couplings that separated the inner and outer crankcases on each side of the central drive case. Its electrical system is crude requiring the use of four separate contact breakers and four coils.
In 1965 Mike Smith of Waltham Abbey built up the crankcases and installed this engine into an MV frame. Mike’s original target was to obtain 11,000 rpm and to use the bike as a sprinter to iron out any bugs before racing it seriously.
I am now dreaming of getting one of these for parading at CRMC race meetings....
That is mental. 200cc 4 cylinder two stroke and a few years before Yamaha and Suzuki decided to copy the idea (sort of).
How about a 500 V four made from say 2 Arrow motors coupled to say a six speed AMC box in a Manx frame.
Talk to Alan Millyard. I'm sure he he could do one. I suspect he's the progeny of guys like Fruin and Reg Geeson and Jones. He can cut a crankcase with a hacksaw to +/- 0.25mm. I'm lucky to get both halves on the same workbench.