MJH, i was not aware of emission standard in China, i knew all bikes manufactured in China are sold in China.

Yes, Scandinavians do fix the performance cam on the bike and also the MV34 Carburetor. MKV34 are Mikuni brand and some are TK brand as used by Megelli 250r.
I guess MV34 are better than the PZ30V carburetors. Change in carburetors will have a noticeable increase in power or re-jetting is a better option?

Honda has stopped manufacturing the engine long time ago.
Have you check the performance of the Honda 250R, it almost have same output with the yingang 250. This is quite interesting. Yingang boost higher compression ration and engine bore. Honda has FI but soon the Yingang will be FI too, will do the comparison.

Im searching for the performance cam for the Yingang 250.