OK, well, I typed "EBC brake pads NSR250" into google and the 6th hit was this one:
http://www.amazon.co.uk/FA140-REAR-BRAKE-HONDA-NSR250/dp/B006MVCMN4
It looks like the EBC FA140 pads will fit the rear calipers of NSR250's from 1988 through to 1995.
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[color=#808080][size=9]Yes,.. I too know how to waste Time and Money,...