Many of us have had the stock gas cap rattle issue. There's all kinds of threads on all the forums about how to fix that. Well, here's a twist. I installed the cam plate upgrade from Herko a few months ago. Ran great but seemed to have more valve train noise coming from the rocker boxes. Lengthened the pushrods a 1/2 turn and that seemed to help some. Still sounded more like my old Sporty than a Twin Cam though. Especially at cruising speed. Very quiet at idle. Sunday it occurred to me that at the same time I did the cams I installed chrome lower air deflectors. The ones that look like fangs. I tapped on them and they rattled a bit. So I took the whole windshield/deflector set up off and did away with the quick release and bolted everything to the trees solidly. Rode to work Monday morning and didn't hear a sound. The engine is every bit as quiet on the top end as it ever was. It was the deflector/windshield mounts that were making noise.