300cc, even 323cc conversion??

[Bazzerro]

Hi folks,

Saw this video on YT a couple of days ago. It's not the first time I've heard of a 300cc conversion but this one goes into it on the rebuild part of the video- the guy/gal doing this just gives bloody likes and never answers the question of WHERE DO YOU GET THESE KITS FROM!!! (You'll spot me in the comments, I even got google translate to ask in Chinese ffs)
Says the motor bottom end can handle up to 350cc, but there's no way this is a "re-sleeve" it must be a whole top end to get the barrels out to 58.8(300cc) or 61mm(323cc), looks like better "tuned"camshaft for it too. Not sure how the EFI is made to work with it(remapped) but says someone got 40bhp out of theirs.....!!!
All google and ChatGPT searches for who the hell it is making these kits has got me nowhere.....

Any ideas, international forums based in the far east? Seems likely that's where they are being made...Would be a superb bike with a little bit more grunt from it!!