I'm guessing garandman is talking about the big bolt that runs all the way across the frame. I did not have much problem pulling mine out, so I ran out and checked it - a 17mm fits nicely on the original Suzuki bolt. An 11/16" socket fits right between 17 and 18 mm, and it might work if the bolt head has been buggered up. It fit a little loosely on the original bolt from mine.
The only other notes I have to pass on about my installation:
1. make sure you loosely put on both sides, then place the joiner piece, then tighten. Otherwise you'll just be loosening everything again...
2. the brackets of the crash bars don't actually make contact with the frame on my bike - the spacers supplied push the bracket perhaps 2mm off the frame.
Good luck with the install!
'07 DL650 ABS
'04 Yamaha V-Star 650 Classic Silverado (gone)
'04 Yamaha TTR225
'03 BMW F650GS (wife's)
'92 Honda XR250L
'86 Honda VT500c (gone)