solved harmonic brake noise
the front brakes on my 03 919 have made two different sounds - one a harmonic hum (which i've read that lots of people have experienced), and the other a horrible squeal (only when brakes are hot).
i did some work on my bike recently, and now the harmonic hum is gone. i replaced my front tire (dunlop 208 on the cycle gear deal) and replaced my 27.xxx mile orginal forks with 3.xxx mile f4i forks (though i don't think these changes had any effect on the brakes). while i had it apart, i coated the BACKS of my brake pads with an anti-squeal product (pink stuff, from pep boys). i think this is what did it. 150 miles and no more hum what-so-ever.
i still get the horrible squeal sometimes when the brakes are pretty hot, but it is not as horrible.
background - my brakes were quiet when i bought the bike. these sounds appeared after my first front tire change (done by a honda dealer). the brakes have been inspected by honda and indy shops, who say they are fine, and squeaking is normal. replacing pads when they were due and a serious cleaning didn't help.
btw - the f4i fork upgrade is awesome - i'll post seperately about that.