Odd horizontal cylinder engine

[Zorge]

I stumbled on "Alibaba" to some company in Chongqing (where else, heh...), which mainly makes/sells tricycles, but among the few two-wheelers, my attention was attracted to their interesting interpretation of a light motorcycle a-la Honda CD.

However, most interesting thing to me is his engine, more precisely it's cylinder head. The crankcase is, as far as I can see, standard clone of small bore Honda. I managed to crop and blow up portion of the photos where you can see the engine.

Beside Honda's, I'm not familiar with horizontal engines the rest of the big Japanese four, so I can not identify this engine or it's head.

So, I ask the simple question: does anyone know what is this?