Just wondering why you had to remove the coolant resorvoir bracket? I didn't have to with my GS, but maybe the GSR is different? Wouldn't you just slide the coolant reservoir up, and set it aside?

But to try and help your situation: http://www.geocities.com/motorcity/d...7/easyout.html
http://www.brokentap.com/easy-outs.html

I would try a tooling supply shop like Do-All, or Tool & Cutter Supply. Hell, maybe even Home Depot carries these?

Good luck!