I had an older 2000 RS
and it would develop a chirping in the front end. I know the belt thing and it wasn't it although it will cause this too, especially right after riding on gravel roads. It would drive me crazy too. I went through everything that was up front. What I found was the headlamp adjusters would chirp on certaing bumps and/or vibration ranges. What I would do to resolve this was to lube the adjusting screws where they slide on the housing on the spring area. That would work for a quite awhile until I would wash my bike one time too many and then it would come back. Real easy to fix. Just spray a good clingy lube into the holes and make sure that you get the whole adjuster.