This has me flummoxed.
I have a weird rattling noise that seems to be emanating from the nose cone area but only under certain circumstances. Any time the nose is pointed into a choppy headwind I hear it. From the sound of it - in my minds eye it seems to be a lose metal washer that is rattling around. The noise has nothing to do with RPM's and everything to do with headwinds. Lower temps make it much more pronounced too. Last night as a passed through two of the Turnpike tunnels it was acting up really bad - as soon as I entered the tunnel it was silent - as soon as I got out of the tunnel and back into a chilly heading - rattling. It's not a huge deal but is is quite annoying.
I have looked all over and just cant see anything that would be the culprit - other than missing fairing screws that go right behind the two from marker lights. I will fix this is soon as I identify the screws needed.
I had what sounded to be a similar noise, kind of a buzz noise, but only happened intermittently, since my bike was new. It drove me nuts for several years because I could not seem to pinpoint where the noise was coming from, but I eventually figured it out. It turned out to be the plastic cowling just above the headlight. Under ideal conditions, I'm guessing, it would vibrate against the plastic below it and cause the buzzing sound I was hearing. I took a small piece of adhesive backed foam and gently pulled the cowling up, the pointy area above headlight, and adhered the foam under it. I did this about a year ago and have never heard that buzzing sound again. This may not be your issue, but worth checking?