Thanks to all for the good ideas. I changed pedals and if a short ride tonight is a true indicator -- problem solved. Rotating the offending pedal spindle with my fingers, it seems like the bearing is shot, feels like metal rubbing on metal. Wild that the symptom is one loud click, but I'll take it as a win. Better problem solved in the garbage than at some LBS 50 miles from home, and I can proudly say I out road my pedals.. Long live the BF.