Givi Tanklock adapter; mounting bolts too long

I ordered a Givi tank bag and mounting flange for my 2001 R1100RT. The flange (BF11) fits the fuel filler ring, but I find that the mounting bolts for the flange tighten up and bottom out before they create a secure fit.

Has anyone had any experience with this? I found one other (year old) identical complaint online, but no indication of how he solved his problem.

I've looked around for replacement bolts, but this is the good ol' USA, and lots of sources don't stock weird sizes in metric fasteners.

They are identified as M5x40mm, but they're about 2mm too long to give a secure mounting.

Hey, Late-Life,

Yeah, me too. Same problem on my '99 R11S, '99 R11RT, and '00 K12RS. You DO NOT want to run those screws thru the tank wall or spin the captured nut, either. I just stacked up some SS washers under the screw heads, even on the countersunk OEM screws on the rear side. Now THAT caused a problem with the filler cap staying open after I unlock it and before I can get the gas nozzle in the hole. That reminds me of a somewhat similar situation I had one time but we won't go there. Anyway, I fixed it by wedging a tiny chunk of plastic under the gas cap hinge which provides enough friction to keep it open at any angle. If your screws are SS you could just grind them off enough to clear. My RT has a plastic tank with captured acorn nuts which didn't provide much tolerance for the length of the screw. The S and RS were different and somewhat more tolerant as I remember. Using the stacked washers I could see and feel the depth of the spacers needed and they cleared everything on the mating lock ring. The Givi system is SOOOO much better than the Cortec, lock ring and bag I have.