Thought I would join this one in case someone has an obvious answer.
Took off carbs (Solex on an S1) to replace the rubber mount which appeared cracked from outside but was fine inside ( should have done it before purchasing new part) Cleaned carbs up a bit with carb cleaner but otherwise left undisturbed. Put back with new gaskets and sealing compound on joint faces. Now won't idle below 2000 and rising as gets warm. Is an air leak the obvious answer as can't think where it might be. Would cleaning of outsides cause problem due to turning carbs upside down?
Anyway any thoughts as due on tour in June.
Dis-connect the rod (15) in the pic and see if that makes a difference to the idle - if it does adjust the end pieces until it is correct