I avoid rain like the plague and can only imagine that, unlike a car' brakes, being fully exposed is not an ideal situation for this. You may be creating steam that could affect the pad>rotor conditions and increasing the heat to the point of attempting a fusion to develop. Scary stuff and maybe a slower speed and occessional applying the brakes to keep them dried off will minimize this experience.
I use ESC's HH-sintered brakes and love 'em - no damage to the rotors and just a minor amount of weear in 10,000+ miles. Use 'em on back in my '07 ABS model and they arere just right to traffic stops and in-the-turn slowdowns.
[B][COLOR="RoyalBlue"]Past:[/COLOR][/B] 1965 Honda CL 305 Super Hawk | 1975 Honda CB 360 | 1989 Honda NX 250 Dual Sport
[B][COLOR="RoyalBlue"]Present:[/COLOR][/B]2007 Suzuki DL650A V-Strom
[B][COLOR="RoyalBlue"]Future:[/COLOR][/B] Just Ride!