might be a XR 400
I think that's quite probable seeing the compression ratio.

might be a XR 400(but I don't think so) that ain't no bad thing one of the most reliable bikes on the planet .
If it's just copied and not licensed by Honda, I doubt it will have that magnificent reliability.

It looks to me it is air cooled
No, they claim oil cooled (practically same thing).

Asiawing SPARK 500
4-stroke 4-valve SOHC single
Compression ratio 9.2:1

XR400
4-stroke 4-valve SOHC single
Compression ratio 9.3:1

CRF450
4-valve SOHC single
Compression ratio 12.0:1

The Asiawing 450 dirt bike they say is liquid cooled, so probably is a CRF450 clone engine.

But it appears the Spark 500 is an oil cooled bike so could be a bored out XR400 or something else entirely. This would seem to make sense as the dirt bike is more expensive.