New air box. Stock jetting

[Jmcb]

I realize that this may be a dumb question. But is they any kind of after market air box/filter that I can put on a 78 gs550 without messing with jetting? I've cleaned my carbs got them back together. All's well. However the stock air box has certainly seen better days. And is being a proper bitch going back on properly. At this point I'm not looking to get more performance. Just want it to run nicely. I don't want to go down the jetting road quite yet either. Is there a flat side box/filter that can just bolt on? Perhaps just stuff with a sponge to restrict air for stock jets?

[LAB3]

If the condition of the airbox is an issue you should be able to find one on eBay, seems like the easiest way to go.