I rattled off the horn when the bike was new...i could hear the rattle and couldn't figure it out then after a ride it was just hangin' on by the wires...was an easy fix...have to remeber sometimes these things are put together by humans...mostly

 

Iv noticed that my risers squeak sometimes. Usually after Iv riden in the rain or it's been washed. I'll keep an ear open for the gas cap, and since I pulled my speedo out I'll listen for that too.

Thanks for the hints!!

 

no rattles from gas cap or speedo here...but at least now I know