Everybody loves a smart-a$$.
No, wait...that's not quite right...??? ;)
(yast yoking..but, you knew that.)
Considering that the 'restrictor' you are referring to is a white phenolic thingy (and not some piece of shop rag), andrew is correct.
Keep in mind that it can indeed be installed upside down (I'm basing this on 'H' model setup. I'm NOT sure it applies to your bike, but check it anyway).
Maybe yours was installed upside down when you took it out? ...and that's what you're looking at?
The air-bender (the white phenolic part...my word) should NOT 'show' any flat spots to the incoming airstream. Look inside the carb boot with the white piece held to it, rotate the phenolic piece 180º and you will (hopefully) see what I'm talking about.
If you have a question, please ask. It's important that this piece go in with correct orientation.