I have a brand new 2010 Road King. I've got just under 1000 miles. I've noticed that the left end of the exhaust pipe has developed a black sut around the inside. However, the right hand pipe is almost as clean as it was when it was new. I think this is a 2-1-2 exhaust system. So I don't think this would tell me that one cylinder is perhaps malfunctioning. Is this normal? It's about time to take it in for its first service. Thanks for any replies.