OK, Goofy Time!
You said originally that this happened at freeway speeds on windy days.
Have you checked the vent tubes hanging down below the bike?
Sometimes the wind can catch the opening of these babies just
right, and mess up your day.
If they are hanging down kinda far, see if moving them helps.
If it doesn't work, fine, but if it does it's the easiest
fix you'll ever do.

Steelheart- '03 Speedmaster Black/Yellow The Hayabusa Killa 16" Shorties/140 mains/Airbox drilled Procom CDI "There is no cure for Celibacy. But we can treat the symptoms."