Hey guys I just got a set of racks for my 85 sx they are hondaline racks in real nice shape. Only problem I have is the rear mounts that come up through the fenders where the knobs would screw into are a little crusty down in the knob threads. Does anyone know what the thread size/pitch is so I can run a tap down them to clean them up? I don't want to guess and possibly ruin them. I don't have the knobs to go off of. I appreciate any help thanks