my jinlun is exactly the same. apparently the tank has 2 skins and when on the centre stand the fuel goes inbetween the two and comes out of the overflow. its because the bike leans over so much. 2 ways to resolve this is either turn the petrol off everytime you put it on the stand (what i do) or get a longer centre stand its up 2 you but that seems to be the only way to stop it
ian
January 2010