Is it just me, or is it endemic to the 88-07 EX250F that the side stand anchors tear out of the stamped portion of the frame?
I just finished breaking down three EX250s (two from a junkyard, one from Craigslist, long story) to make one good one, and all three frames had trauma to the side stand anchors. One of them, the one I got all the good parts from, had one of the anchor nuts entirely torn out of the frame, with nothing left but a jagged hole.
My solution was to cut a chunk of 1/8" steel to fit between the side stand pivot bracket and the frame, and MIG weld it to the frame. I normally don't weld on motorcycle frames, but I figure that it is highly unlikely that the stamped steel portion is heat treated. And if it does go bad, I'll just switch to one of the other frames.
Here's a sketch of the reinforcing plate I welded onto the side of the frame. Apologies for the inch-based dimensions; that's just what I usually work with. For reference, the center-to-center distance of the two holes is a nominal 36mm, but the side stand bracket that goes there has one of the two holes slotted out by about 2mm to accommodate variations in the frame welding.