well fred you need to try and drain the fuel off rom the carb to see if your right,on most chinese 50's they have a remote fuel drain in the form of a pipe leading from the float bowl down to the front of the transmission cover undo the small screw in the end of it and see if any fuel comes out if it does then i think there is no fuel prob if its empty then your right.the fuel has to go from the tank to a vaccum tap then to the carb so if there is no fuel in the carb tne either your fual tap is faulty or the vaccum pipe has come off it or off the carbs inlet manifols or the tank is empty.as a pointer the valave clearances tighten up on these bikes alot and you should give the valves a qucik clearance check ,set the inlet to .05mm and the exhaust to .08 mm.do this regardless of the suspected fuelling problem mate.
adam bike doctor(of milton keynes motorcycle centre), November 2010
