I believe it's a lifan clone. Which is kinda weird because they don't have vertical 250cc engines (that I can find anyways) But this looks pretty close. Maybe someone can verify the measurements on the print there..
http://www.hooperimports.com/product.aspx?pf_id=E2005M
After further web surfing I'm now convinced that these are actually 200cc engines... and man that makes me angry :x Can anyone confirm that they are or are not 250cc engines? Thanks