respectable decision. Wish Id've known before hand to get 550 as opposed to 450
. Still...despite all the PITA measuring and such I had to do I'm convinced of the benefits of this mod both style wise and ease of repair (assuming you dont break the bead if you go flat). Im combing bikebandit with a fine toothed to glean all "apparent" transplants. As I said the vast majority of 450s will be a super PITA and barely worth the trouble IMO however...the P/N for the '83-'86 550Ls you two are running is 730781-001. Most 450's have 512988-001. thats what Ive got. No good. A possible 450 match up is an '82 GS450TZ P/N 730784. Another possible match up may be an '82 GS750TZ P/N 730785. Im just going by P/N similarity and drum compatability as of now. I'll look into it deeper as I go along so those wishing to switch dont have to deal with the BS i did.
edit
After looking further into strictly GS POSSIBLE transplants with drum brakes and the "star" spoke design I have found...
1980 GN400T - 730778-001
1981 GS450TX - 730783-001
1981 GS450LX - 730779-001
1982 GS450TZ - 730784-001
1982 GS750TZ - 730785-001
1982 GS400TZ - 730280-001
1983 GS450ED - 730782-001
83-86 GS550L - 730781-001(sure thing)
Most other models seem to be disc brake, spoke wheels, both, or the 450 512988-001 I have which...well...im sure you know by now.