have a 08 fat boy had 1000 mile service done at dealer.
at 4000 miles i changed oil my self to mobile 1 v twin
have 4900 miles on it and noticed oil level drop a little about a 1/4 " below the mark
is this normal.

 

If you filled your oil tank so that the oil level was at the full line, then yes this would be normal. When you change your oil, only fill it up to about 3/4 of the way to the full line. If you put more than this in, it will end up being blown into your intake because of excess pressure built up in the top end. Don't worry, it is designed to work this way so it wont hurt your bike, but that's probably what your problem is.

Chris

 

yes sounds right to me have filled about a 1/8 "abovethe line when hot
thanks for advice

 

Yep, it's normal. The engine heats up, the oil level rises, and some will blow out the vent tube or out the intake.