kz550 start problem

Hey everyone.
I've been fixing up an 81 kz550 ltd. So far I've installed a new battery new spark plugs and I converted the pod filter the previous owner installed back to the air box. I also added new oil, oil filter, and gas. I put it all back together and tried to start it and the bike won't run with the air box cap on without cranking the starter motor for a few seconds on full choke. I bought the air boxbecause the bike didn't run well with the pods but it does turn over easily and idle. With the air box installed the starter motor just cranks and nothing else happens. I thought it could be the jets in the carbs but they were too frozen up to see the size numbers on the jet. I'm out of ideas. Does anyone know what this could be?
Thanks
Nick

It's quite possible that the previous owner fiddled with the jetting when he installed the pods, so you will need to see what he has done. I would soak the jets with Kroil for a few days and then see if they will come out. Ed