I have a 1985 FHLT, and in the past few weeks it has been fouling plugs alot, when it does it will start popping out the pipes at a normal cruise, just yesterday i noticed that it looks like that the front head had a plug stripped and a steel insert installed and i believe that is the jug that is doing the popping after time goes by, would it be caused by that steel insert not letting the plug dissipate the heat and fouling it after awile.