Sticky float needles?

I'm still trying to get the carbs for my dad's bike to work. I don't have a ton of time to work on them, but I had some today so I'm trying to get them sorted.
I originally rebuilt them a bit ago. Ordered an ebay part kit for the fz600/ yx600 carbs, everything looked good, I made sure all the new orifice sizes were the same with some drill bits (dull end, I didn't scratch them up).

I've been trying to get the fuel levels to the correct level for a couple weeks now. Playing around with them, at first they were all way too high. Adjusting the floats didn't seem to do anything either. I ended up using my calipers to check the depth of the float needle seats, and the sealing surface was between 30 and 40 thou higher on the new seats than the old ones. I swapped the seats out for the old ones, as they still looked perfectly fine, though a little brown from age and fuel exposure.

I managed to get the fuel level a bit more dialed in, but I'm experiencing a new problem today. The fuel level on all four carbs is within a couple mm of where it should be, but now it seems like the needle valves are sticking.
The carbs will rarely fill to the proper level now, instead they either dramatically overfill or barely let a trickle of gas into the bowls. I imagine it must be the new needles, maybe in conjunction with the old seats. I have managed to get the needle to stick with the bowls off a couple of times. Maybe I was experiencing this before but just couldn't tell with the weirdness caused by the incorrect seat height.

Didn't see anyone else with this issue, but the search function on this forum seems a bit useless. If anyone has any advice, measurements of correct needle valve OD's, valve seat ID's, or tips and tricks to get me going, I'd be most appreciative.

 

Incorrect float valve length can change the geometry and cause issues with doing wet set on the carbs

Or in this thread it was reported that the float "droop stop tab" was incorrectly set causing issues with the aftermarket float valves

https://www.xjbikes.com/forums/threads/mikuni-turbo-carbs.129817/#post-656815

You can use Google to search by qualifying the search criteria site:

carb overflow site:xjbikes.com

 

can you post pics of the needles? Does it have a single or dual wire that goes over the back end where it slips onto the tab of the float?
Also, is there a lot of play between when the float tab pushes on the needle vs pulling on the wires? If that gap is small, it is better IMO as the float will pull the needle open sooner vs relying on the needle to drop due to weight. This helps overcome any "stickyness" of the rubber tip to the needle valve IMO.
I ran into that issue with one type of needle I was using that had a single wire on it and a huge gap.
If you use the old needle valves, did you polish the inside where the rubber tip of the needle touches? I used flitz, but compound will work. Need to clean that up and polish the surface some IMO.
Did you set the floats dry and measure the float hieght before wet measuring for 3mm?
Also, did you test your floats? put them into a bucket/bowl of water and make sure all the floats float the same way. If one tends to look like its sinking lower than the other, its defective.

 

The needle valves do have a small gap to them, but nothing too crazy. I took pictures of one of the needles, you can see that it's a single wire that overlaps where the tab goes through it. I ordered some new floats from Derek at Motolab, will hopefully make the difference. The fact that the fuel level will stick closed, and then stick open, seems to indicate a float issue to me. Polished all my seat surfaces extra well today, I'll see how the floats work on Wednesday most likely.

 

With the taper in the wires, could it be possible that it grips the float tab sometimes? Hard to tell from the picture.

 

Got it sorted. I purchased some new floats from Derek at Motolab, they instantly solved the problem. The ebay floats had no bronze bushing in them, and had a very different tab angle at 20mm of float height. putting in the new floats made the fuel level stop doing funny things and let me set it with ease.