The Japanese manufactures are not interested in moving production of any existing engines they currently manufacture to China. The GW250 was engineered and designed to be manufactured in china. They did that with the intention of globally exporting that new model as well as selling it domestically in China.
The main exception is the YBR250 engine, I wonder to this date if it is actually entirely manufactured in China, some claim it is but it is also manufactured in Japan. That is not very efficient to do, that being having more then one production center for an engine.
All of the Japanese manufactures are not interested in expanding the model lines in China without protection and to them that is independence from the partners. The Chinese obviously want that as well, but they want more technology first. The adage is they want you to provide the rope to them that they will use to hang you with.
Realistically they could vie for the LC250 production, that engine has a very limited release, if they could bring it to the production it would displace some of the Yamaha V250 sales. But not only as a cruiser it could be brought to production in a standard frame as well , like the SRV frame.
I believe that Suzuki 248cc V-twin offers more power then their current 250 single, it also bests the Yamaha engine as well.
VL 250LC
http://www.motorcyclespecs.co.za/Gal...001%20%201.jpg
SRV 250
http://www.thaiscooter.com/forums/at...1&d=1329476229