Informed speculation here Max without disassembly and pics. You have to remove the wheel, chain, guard and shockies to set the "drop" so, do that and torque it up as 5T suggests. If it still waggles, you may as well take the swing arm out.There is beaucoup information for bushing removal on this forum so you could search that up and follow the instructions - a bit of careful hacksawing and hammering but it is owner do-able. Any decent machine shop should be able to remove the old bushings and pop in new ones if you're not inclined to wrestle with it yourself. The end seals are available from Yamaha as are the shims that take up any excessive space between the bushing face and the end of the inner tube, (which should extend a couple of thou past the bushings). I got shims from Heiden, a little pricey for what they are, but effective. If you do strip it down, look for the shims to be "greased" in place inside the swing arm seals. They are thin and easily missed. Mikes sells the inner tube, (Arctic's reference), if yours is worn but there have been questions about the length so you might want to eBay an original in good nick. You can drill a couple of extra holes in the inner tube to facilitate lubrication and fit a grease zerk in the upper middle of the arm. Any competent home mechanic could do it all in an afternoon. Took me a couple of weeks but then, I had to wait for parts and my competence is a matter for debate.
Cheers