from what other's on here have said... it's not possible to swap a C1 motor to a '7r. only the previous generation 7r and 9r's swap because 9's motor was just a "stroked" version of the 7's.
also note, i once owned '98 9r so i tend to believe 'em. it's so wide, that thing looks almost "air-cooled". LOL now that's not to say it's "impossible", but just to say it wouldn't be easy...

'98 was the first year of the change from the "B" chassis to basically the current design of the '02 (it may even be considerd "D" by now?). the 7r however has yet to change since... what... '96...?
it's probably going to be any easier (a relative term here) proposition to just do the bore kit that brings the displacement up to and around that of 9. i made a post a while back (before the boards crashed) where i had checked into the maximum displacement possible for both the current 7 and the 9. i forget now (arrrgggh), but i think there's a billet cylinder and head kit that'll get a max of 940cc's out of that mill...? someone correct me if i'm wrong...