As many of us know tracking down those pesky unknown sounds can be enough to pull your hair out

(if I had any left

). This one is driving me crazy and shy just spitballing and throwing money at it I am running out of ideas. I hear it mostly around 30-40mph (but I think that is because wind noise is lower but speeds are high enough) but have heard it at freeway speeds too. It sounds like someone ringing a bell (no, its not my gremlin bell, already eliminated that) or a loose shock cover (again not it). I think it is coming from the front of the bike but it is hard to tell at speed. It is very intermittent only lasting 1-2 seconds (or less) each time and only a few times a ride. Even if I can't stop it finding it will at least let me sleep better at night. I have gone through and tightened every bolt to spec that I can find.
Any Ideas?