Coming 14 years after BMW ceased production of the R1100S I realize that this thread may not be that interesting, but maybe it will help someone trying to keep their old bike roadworthy...
Oh-so-long ago I started
this thread. I was concerned that the weld-back-on rear tabs on my bike were in the wrong place.
Recently I had the opportunity to measure the rear tabs on a couple of BCRs that a friend owns, while I was in the middle of resurrecting my old steed. It had been parked forlornly in a corner of my hangar, having only accrued about 500 miles in the last three years. A couple of careful measurements of said BCRs, compared to mine, made it obvious that the dumbass who welded the tabs back on my bike either wasn't careful or didn't care (probably both) about getting them in the right place. He managed to add a bunch of material, effectively lengthening the tabs by about 6mm. No wonder the tupperware never fit right. There was a gap of about 15mm between the bumpers on the front of the saddle and the back of the tank plastic; I could sense (and see) the front of the saddle collapsing to close the gap when I rode.
I decided to finally take action to correct the problem that I'd been mulling in the 11 years since I started the above-linked thread. This photo, gleaned from yet another thread about broken frame tabs, inspired me:
