Sorry guys, I do appreciate your input. Here's the story. I bought the bike from its 3rd owner. Had a pre purchase inspection done at Motoghost, a strictly BMW mechanical shop only in Phoenix; they have the very best reputation. The owner took my bike for a test ride and noticed a pulsing in the front brake, checked it out and determined that the left rotor was warped. How or why I don't know; the right one was fine. Appreciate your help.