After a couple of days of labour/learning, the Chinese bike seems to be running smoothly! Had the rear wheel off yesterday and tidied up the drum, greased the arm etc and now works smoothly. Today after discovering the massive oil leak yesterday, i have drained all the oil which appeared to be about a litre too much, mopped and cleaned all residual oil and replaced with correct amount and decent motorcycle oil. The engine sounds and feels like its happy to be running, which in turn makes me happy in the knowledge that i can be free to ride again. Lets hope it lasts :-)