I will remove one bolt from the steering damper and see if there is still resistance there. I will also check the mounts for it, but I do not think these mounts have rubber in them.
It may well be the large rubber insulators which hold the mount to the frame, but I could not duplicate the noise from them. And I agree, I need to solve this problem.
To address the shock question - I have no reason to believe the shocks have ever been replaced. I was going to crawl under there this weekend, and check the shock mounts, as perhaps the rubber in there has deteriorated?
Thanks for the replies and the help, I will let you know if and when I find it.
1989 560SEL (172k)
1989 325IC (122K)
2004 Suzuki Volusia LE (3500 miles)
2005 Yamaha Road Star (20 K miles)