My carbs are running rich. So rich, that the two center plugs are moist with raw gas, and the two outer plugs are black with soot.
This is on a '83 KZ550 LTD. Do I adjust the floats, the idle screw, what?

 

I think a good carb rebuild is in need. At least clean out all the jets. Then sync the carbs afterwords.

 

At least check the float heights and do as mentioned above. Then place your sync gauges on to see where that would be. Also rpm range of when your issues are happening would be nice along with elevation.

 

I've cleaned the carbs out twice now(I did not think to check the floats either time), and synced them twice. Once with the old performance muffler on, whichhadno baffles and packing , and the second time after installing factory original style muffler.
I have problem with the dial gauges during syncing, in that the needles fluctuate badly, until the RPMs are up around 3000. However, most of the running has been with the bike at idle, working on it.
Right now there is a foam style airfilter in the bike, not a K&N but similar. My altitude is about 450 feet above sea level.

 

Then just check your floats? For ****s and grins?

 

I think you need line restrictors on your sync gauge. That should make the needles more steady, and easy to read.