Air screws/pilot screw limiter

In the engine forum someone asked to identify what two screws were, andthey were identified as the air screws. So i am moving my question to the carb forum... Are these screws (air screws) the same as the pilot screw limiter? My bike backfires a bit and i checked the plugs and found some carbon build up as well as improper gap. I "tinkered" around with what i know as the pilot screw limiters and the idle adjust and reduced the backfiring considerably. will this probably help with the carbon build up as well?
i just have serious doubts that those screws were in the correct setting.
btw, my bike is a 1980 KZ750 twin, if that helps.

According to the carb diagram in Kawasaki.con, the 1980 KZ750 twin came from the factory with constant vacuum (CV) carbs, and a plug in each carb covering the pilot mixture screw (to help prevent us EPA-declared low-life incompetants from being able to mess around with the pilot mixture). The carbs in the photo are manual slide carbs (not "cv" carbs) and don't have either a plug or a limiter. A "limiter" was sometimes used instead of a "plug" to allow a very limited adjustment of the pilot mixture screw.

Am guessing by this time most carbs' plugs and limiters have already been long since removed to thereby allow unfettered adjustment of the pilot adjustment screws (some are pilot mixture screws, whereas others are pilot air screws).

The question: Are these screws (air screws) the same as the pilot screw limiter? The short answer: NO.

As to reducing the backfiring, am guessing the pilot mixture was enrichened, which reduced or eliminated the backfiring. Am further guessing there are no longer any plugs over the pilot screws, and no longer any "limiters" in place to restrict movement of the pilot screws.

Where plugs are yet to be removed, great care must be taken so as not to drill too deeply, because the pilot adjustment screw head is directly underneath the plug.

Good Luck!

definately no plugs over the screws. is there an ideal setting? it will be tomorrow before i can get the bike out and see how much effect i have really made by tinkering.