Yes, look up the "earshave" procedure on this website for a full explanation of how to remove the emissions gear. (NOTE: you probably do NOT need to re-jet as is indicated in the "main" writeup. #42 pilot and #142 main is WAY too rich)
If you mean the charcoal canister for Calif emissions, you can lose it and cap off any vacuum lines, if any. I haven't actually seen one, but the Calif. bikes have them. Just be sure you keep the gas tank vented.
Otherwise, it's as uber said for the airbox.
Coaster, is the term used here for the plate to cover the reed boxes, or those can just be plugged or capped.