Motorcycle Repair: Sportster using oil, exhaust pipes, pin clip

Question
Last summer I purchased my first Harley.  It is a 1999 Sportster XL1200S.  I noticed it was using oil, not a lot but enough that I was sure to check it often.  The bike only had 2400 miles on it at the time of purchase, so the guy didn't ride it much.  I have since put about 5000 miles on it and this summer while washing the bike I noticed oil in my exhaust pipes.  The bike has had all the routine maintenance done.  Do I have a valve problem? or some sort of blow by?

Answer
There are two ways that oil can get into your pipes. One is going past the rings and the other is going past the valve guides. Even though the bike has low milage the guy you bought it from might not have broken it in properly. Overreving or riding hard when new will cause this. You might also have a broken ring or a broken wrist pin clip.
The longer you ride the worse it will get.
I would remove the top end and do an inspection of the pistons and valve guides.
Good luck and happy riding
Mike