I should have also added new rider...
I've had my 83 KZ550 (not the LTD, the regular belt-drive) for all of a week, and I've been nothing but thrilled with it on my short "getting comfortable with riding" trips around town. Then, when I took it out on the highway for the first time, a loud rhythmic knocking sound started. I noticed it around 60 mph, but the noise continued as I decelerated and shifted until I got below 30 mph. The shop is looking at it now, but when they took it out for a test they had no idea what it was. It's definately transmission-related. Any ideas?