[mousitsas]

Better keep the original narrow band bungs plugged and get the bike to a shop to weld a new bung for the wide band.
Remember also to plug the SAS if you haven't already done so!

Edit...just realized that the thread is the same (no?)...so to dremmel the 'lip' inside the bung I think is a fine proposition....If you are worried about the shavings maybe you can stuff an oiled piece of cloth inside before, which you then remove.