idle problems tick over problems

Can I just say at the outset that we have had major issues with this problem, and the help contained within this forum has been invaluable. I have posted this as a seperate entity in the hope that it will help others that have a similar problem. The bike concerned is a 1984 XJ 750 fitted with Hitachi carbs
The carbs have been cleaned, bores polished and valve clearances set, in short all advice in forum followed, however bike still had one of following problems
Problem 1: Bike runs fine, will idle ok but when revved over 3000 rpm, it wont return to idle, just revs at 3000 rpm or more.

Problem 2 : Bike runs fine, revs to 6000 rpm plus, returns to idle speed normally, but will not idle, will cut out.

After spending hours following advice on the forum, it transpires the problem was a very small amount of corrosion that was not removed during the cleaning process. It was found when the mixture screws were removed. The solution was simple, remove all four screws, clean using small amount of carb cleaner. The bike now runs sweetly, revs to 6k plus and ticks over about 1.1k. Hope this helps someone avoid the frustration we experienced.