Hello dear motor talker, I have an annoying problem with my XJ 650 from 83. The motorcycle gives full throttle on its own. It starts clean, but turns high after a second and hangs at high speed. I have open air filters on it, but the motorcycle ran with those earlier without any problems. What I have already tested: – Gas and Choke rope hoists have nothing to do with it – Idle speed control screw brings no change – carburettor has been cleaned, all membranes are healed, all nozzles free – mixture screws turned out on 2.5 revolutions, no change – intake nozzle and seal new, no improvement – petrol tap membrane works perfectly. – The carburetor is synchronized – the spark plugs are a bit black, so the motorcycle seems to run too fat. Don’t understand exactly what the cause is. Does anyone have another idea? Thank you very much am desperate.