Ok I am riding along and everything is fine. See another guy with an Argo and stop to chat for about 15 mins. Go to start up again and Conquest starts and I hear what sounds like a rod knocking( or detonation). Rev it up a little and goes away for a sec and comes back. Limp it back to my truck and pull the rear spark plug. Center electrode is missing. Run to Farm and Fleet and pick up a couple of champion O.E. replacements and replace both( front one looked a little carboned up anyway) Ride for a little maybe 1/2 hour and start bogging again. Load her up on the truck and drive home. Tonight I pull that rear plug aagin and again the plugs center electrode is seperated from the stem and sorta like a little melted ball stuck to the arm electrode. Compression on that cylinder is 210 cold and 220 on the front. Any suggestions?