Blimey--bad shop. That's a crying shame. So lets get to the crux of the problem--or 'is' there a problem. When bolted up you 'should' be able [with no shocks on or wheel in] to be able to feel a rubbery springy feel pulling up or pushing down on the end of the arm. Will be Very rubbery Springy & not move far each way but return to central. What was the reason for replacing the bushes as i recon they 'never' wear out. If you had 'any' sideways play or movement in the arm it would 'only be' because the main nut wasn't tight enough & was moving on the long through bolt. Not uncomon & have seen it lots over the years on smaller 125 road bikes with the low exhausts hung off that bolt & it eventualy comes loose & moves around. Sorry i do go on i know. Hope the shop didn't charge you anything or bought you a new S/arm.

I guess I figured they were 50 years old and should probably be replaced since they were rubber. If I had to do it over again I would have left them alone I think. I was able to get the 3rd swing arm to about 97%, still a little off but close enough to go on the bike, get the bolt in and shocks mounted up.

Thanks for the update & hope it works out. Happy mine are still good from 1970. Good old Yamahas eh!!. Reminds me of motocrossing my 500 BSA in the "60's ["54 road bike modified] had those same style bushes & i blamed the rubberyness [is that a word] for getting dumped off through getting in big end swaps at the wrong moment. Lock to lock then spat off like an imposter haha.