if you "had" the original airbox then you had the 4 original rubber velocity stacks, you might want to get them back and put them on there, same with the original carburetor parts if you can get them.
Nobody changed the engine displacement or the size of the valves, so no change should have ever been made to the carburetor jetting. The notion that you need to put more fuel into the engine because you have put more air into the engine after installing pod filters is a complete misconception, your engine moves the same amount of air through it as it did before and the previous owner was an idiot to put cheap pod air filters on the mouth of a CV carburetor. If that worked Suzuki, Yamaha, Honda plus every other engine maker would have done it that way to start with and profited a whole bunch more money.
I was the idiot who put those on as I didn't know about velocity stacks at the time. Also, I still have the airbox, but the stacks were hard old rubber and would not go on the carbs. If I could get some new stacks, from Z1 maybe, I could try to put the box on again. The dealer that sold the bike 40yrs ago said that the motor had to be off to put the airbox on, and I'm not taking the beast back off. Also, the 42.2 pilots were in the carbs when I got the bike (which was weird to me because I thought stock was 22.2. Could be wrong), and the bike wouldn't run at all until I put the 140s in.
Backstory: Bought the bike bone stock, tore it down to bare frame, repaired, repainted and/or replaced everything on the build up to a cafe racer, substituted a 4-1 Delkevic straight pipe setup, substituted pods with filter foam inserted (per a forum suggestion), and adjusted the mains until it ran, didn't touch the pilots because they were already big enough as it seemed to me.
Remember this though; I just got started in motorcycle building eight months ago when I started this build. Most of what I know about motorcycles, I have learned in that time through trial and error. Anything else, I learned from forums. If you could tell me how you got the airbox back in, fantastic. If you could tell me what size your pilots are, I will try that size. I'm still learning here, so bear with me.