Squeak after tire change

[85GL1200I]

This started in June, so not really a new, but a continuing problem.

Had a new rear tire mounted, and re-assembly was a pain as usual but was finally completed. Since I got back on the road I have had an annoying squeak. At first it was difficult to tell if it was coming from the front or back, but a short ride without the helmet located the noise from the back end. It seems to lessen in warm temps, and get worse when the bike is cool. Makes me think it is a rubber part. It is suspension related, only hear it when hitting bumps. I cannot re-create the noise with the bike either on the side stand or center stand. I thought it was the rubber pieces between the bags and rear bumper, but I removed those, cleaned and coated with WD40 to no avail. I think I may remove the bags and go for a ride.

Any ideas?

I know, turn the radio up.