I got the motor back together with new tranny ball bearings and it runs great but shifts intermittently.   The shift shaft return spring is the big spring with its two ends crossed that go on either side of a tab in the shaft plate.  Neither the Clymer manual nor the Factory manual give explicit instructions on how to fit that spring back on.  I put it on with the ends of the spring crossed.  There didn't seem to be much pressure exerted on the tab.  I raised the question to my local Suzuki dealer, a guy who is supposed to know GS 500's and he said they go on like that.  Well now the tranny shifts really iffy, won't go 3, 4 or 5 without a lot of teasing the shift lever and cursing. 

Can someone tell me if that spring goes on with the ends of the spring crossed or sprung parallel to each other on either side of the tab.

There was a thread somewhere here about 6 to 8 months ago where someone had the same problem and I recall the ends do not get crossed. There were pictures, too.

anyone remember that thread?

Yah, the spring ends need to be sprung outwards so that they sit parallel on either side of the tab in the shifter plate.  Totally undocumented in the Clymer and Factory manuals, besides which my local Suzuki dealer supervisor gave me the bum scoop on this.  It was an easy fix.   If you want something done right, you gots to do it yourself.