Fuel tank mystery leak

[VFRhugh]

Anyone ever had a fuel tank leak under the cowl band? I thought it was coming from the cap but disproved that today. Only noticeable after filling up. Only leaks while driving. There is an annoying noise from the tank when less than half full at certain rpms. The next obvious step would be to look under the band but I thought I'd ask first. Not sure how to remove and not destroy something.
Hugh