fast idle

[buddy]

I have an 81 xs400H I bought it from someone that had made a lot of changes. I got everything back in good shape but I have a question about carb tuning. I cleaned them until all passages and jets were open 1 carb had a copper float and the other didnt. 1 was missing the idle plug so I replaced it. when I start it the idle is fine but when I rev it up it is slow to come back down to a idle. I used carb sync guages to syncthe carbs and if i have one lead the other a lot the idle comes back down quickly. I did install new manifolds.
If any one can point me in the right direction I thank you