Everyone hates removing carbs with an airbox. Maybe this will help. It is on my 82 KZ650 CSR but I also do it on my 77 KZ650 B1 and was taught on a 76 KZ900 LTD to do it this way.
#1 is you must have new or SOFT boots.
To remove the carb bank push the boots into the airbox. Once you have done this the carbs will come out easy with plenty of room.
Now for the part everyone hates
Installing the carbs
#1 Remove the boots from the airbox
#2 Now fold over the outer flange on itself. It's pretty easy.
#3 Now put the boot back into the airbox as it should be but with the flange folded over. Pay attention to position the boot correctly as the outer ones are curved. Usually a pin and notch shows the position.
#4 Now you have an extra inch to slide the carb bank back into place. DO IT!
#5 With the carbs back in place and secured, unfold the folded flange onto the carb throats (easy), install the spring keepers and Bob's yer Uncle.
I hope this helps make a tough job easy and convinces some to stick with the airbox. Pods look nice and all but they do come with headaches, a learning curve and not everyone has the expertise or wants the expertise to make pods run good. Above all make sure you do your homework if you are thinking about removing your airbox. It is not easy to remove and harder to re-install if you get disappointed by the pods. Above all else NEVER destroy your airbox to remove it. You will find a hard time replacing it and at the least you might get some money for it from someone who didn't listen up. This tip will at least make working with the airbox easier. Good Luck