1981 kz650 cut shock springs?!

So today I noticed my newer rear tire is slightly more worn on the chain side of the tire. (Nipples are gone on that side but not the other and the dust from the road is further on that side as well) then I noticed that the previous owner CUT the bottom of the shock springs. Could this be the cause of my uneven wear? He gave me another set of rear springs but one is missing a bushing and I'm not sure how to get a new one in

To swap bushings I used wrench sockets & a C-clamp.  silicone spray lubricant helps --- LiquidWrench brand is a good one.

I would check the chain alignment to make certain the rear wheel is aligned right.  and check the axle spacers.  It's not uncommon for this stuff to get installed in the wrong order.  It's kind of a pain, but I would pull the rear wheel to check everything. maybe not necessary, but that's what I'd do.  If not done already & you don't know the age of the Rr brake shoes, replace them.

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and while you have the wheel off, you can check the condition of the bearings.