I wanted to upgrade from the stock swingarm, it has two cracks in the welds, can I use a swingarm off a 1987 LT250R and put on a 1985?
yes you can, but you will need the shock and everything that bolts up to it for this to work. from the newer bike.
I have a shock assembly off of a 1989 LT250R, and a 26 spline axle from a 1991 LT250R. Is this all I need, I can use the swingarm bolt from my 85 to mount it to the frame right?
yes bolt is the same, i think the shock linkage is the only thing different, and the sprocket hub on the axle