Sorry Terry, I missed your post.
However unlikely, I hope the rattle stays away!
Your post reminds me there are still a fair amount of aftermarket engine parts for the 1000/1100, and ebay does make it easier to find chassis parts as needed. I'm not sure that Suzuki keeps parts for discontinued models like the gs series as well as Honda did for the cb's, but with group support, it seems like restoring or maintaining a gs should be fairly easy as far as parts supplies go.
I'm still impressed by the sump extender fabrication!
I also didn't care for the way the R100 front end was designed, and had bottoming issues. BMW calls for very thin fork oil, I think 6wt. I went to 10 or 12wt which definitely helped( 2 seasons and I still have the new fork seals I figured I'd have to throw on, in a box). I think you mentioned you went with the Progressive springs. I remember those, I think they were shorter and used slugs to stiffen the front end, didn't they? I have some new oem ones, but they're still in the box with the seals.
I also love the look of the BMW handlebar fairing, and was going to put one on until I heard all the buffetting stories.
There's a few other hassles with the r100 models as well, sidestands, rear wheel removal etc. On a bad day, I call it !@#$%^&*.On a good day, I call it character.
All best!
Ben
G'Day again Ben, well the "loose" rotor is a possibility, I didn't ride it for awhile because I thought I'd done some damage to the crank after one "spirited" ride (90 MPH in second gear at 10K+ RPM) when I got a rattle on the alternator side that wouldn't go away. I left it for a month and fired it up again, and it'd gone away. Hmmmnnn, self repairing bearings? Doubtful.
This engine isn't the original, I fitted Yoshimura 1085 pistons and race cams in my original engine, and this is the stock "spare" engine out of another of my GS1000 bikes, but it had a stuffed valve so I installed my original engine's top end and oh, now it's just confusing, ha ha! I do have a set of NOS Wiseco 1170 "Pro Stock" 15:1 pistons (they don't make 'em anymore, apparently) and some "Ivan Tighe" cams to eventually go into my original engine, (I sold the Yoshi gear) some Mikuni RS flat slide carbs, etc etc, but this engine is otherwise so sweet, I'm in no rush to trade "easy riding" with "Jekyll and Hide", ha ha!
The thing with the R100RS I had, was it was great on fast sweepers, but got "tied up" in really tight stuff with the skinny long travel forks etc, but tuck down behind that beautiful fairing, and not only will you stay dry in a torrential downpour, but you'll stay "arrow straight", it's just that good. Conversely, the R90S fairing I had on mine for awhile just accentuated the speed wobbles, much like the horrible (but really attractive) Suzuki GS1000S handlebar fairing.
The sump extender was easy, I just bought a slab of 1 inch thick alloy plate, and traced the sump pan's shape on the outside, and used the sump gasket to trace the inside, cut it out with my big Bosch jig saw, and used a new gasket top and bottom, with one inch longer screws. I also had to move the top brace of the centre stand down an inch to clear everything, but it really wasn't that hard. Cheers, Terry. 
