I have a 200 road king and there is a high pitched noise similar to one of those test pattern tones. It has been loud at times but of late is more subdued. It shows up usually at the 3/4 tank mark and will stay for a 100 or so miles and then go away for a while then return. I had one mechanic say it was fuel pump noise and that the only way to get rid of it was to replace the pump. What do you guys think.