I have an 05 RKC. The front head pipe (exhaust), first 5-6 inches from the head has turned gold in color. tI suspect his happened 2 yrs ago on a very hot/humid day on a long run, some of it was city, it did backfire a little on that day also. I am no mechanic by any stretch. The shop I take it to replaced the o-ring gaskets by the fuel injectors becuase they were in bad shape and might have had something to do with it runing a lil hot. The mapping was re-checked and I'm told OK. Before purchase, the bike sat for three years in an unheated airport hangar in Michigan, (only had 1,500 miles on it at purchase). It has a Power Commander, Arlen Ness Big Sucker and as far as we can tell Boom-Can Slash-up slip-ons. It is running good now, never backfires only that one day on decel and the browning has not increased in color or length. How can I remove that gold color from the exhaust?