I have a knocking noise as I pedal my bike from the bottom bracket area.I tightened the sprocket rings.I tightened the cranks.I changed the pedals and chain and freewheel and nothing helps.When I took off the cranks I rotated the bb bracket and though I didn't hear any knocking there was a clicking feel. Is that normal?The knock is once per revolution while the right pedal is abought at 2 oclock.Is the next step replacing the bottom bracket?The bike is an 85 trek 760 with all Campy Century components.What type of BB would it have and what tools would I need to replace it?Thanks in advance!