.....Or 60 grit sand paper more like it.
Just to add what Scotty has said about the tail section. Do ensure that the notch on the front of the rear fender is fully seated in the rubber bush that is below and behind the seat. It's not easy to see, Try looking from the under side of the fender. I think I posted a pic of it in your last post. THIS IS A MUST ! If it is not seated the entire tail ..fender..and both fender stays will wag. It will get worse as speed increases, and more air is rammed under that high set fender. The faster you go, the more the tail wags, then so does the bike.
I've tested it by removing the entire tail. running the bike to around 80-85 mph, with the higher tire pressures stamped on the plate. The bike was rock solid..... Reinstalled the tail , with the fender seated correctly, still with the higher tire pressures. It was better, but like yours bittercrick....not like it should be. That's when we dropped the tire pressures, and it worked. Sort of sounds like yours?
I would also check your swing arm pivot bolt that it is torqued correctly. You may also want to add some washers , to fill that extra side to side play at the shock mounts. Upper and lower. The idea is to get rid of any excess sway or wag in the rear, that will resonate up the frame, and upset the stability. It worked for me. also, Spin your wheels, do the rims look like they are true and round? Any excess hop or run out? Fork oil level the same in both Legs? Mine wasn't. Could be one thing...could be a few things adding up? Like is was said earlier. It should have been test ridden.