Spoke to the factory, they had a guy with really decent English, he said the engine was originally a Honda developed 450 single. Whether this is an officially licenced Honda engine or not I'm unsure. The guy said they make the engine themselves.

So this probably is similar to the CRF 450 engine. In fact this probably is a CRF450 'clone' bike.

Cost quoted was 26,000 RMB ($3,800 US), if in China, other markets prices will vary.

I will probably visit the factory in the spring or as soon as the weather is acceptable.

Honda CRF 450