Here we go the oil discussion. I changed my oil and filter from the stock oil @ 300 miles. Never over 5k on the rev counter (sound so European) Took it easy up to around 700 miles and took it in to the dealer for my 1000k service (yes I bought the service agreement from dealer) At the 1000 mile service I switched to 20 50 Mobile One in the engine. My service manager and my Screaming Eagle teck use Mobile One in their own personal bikes. Recomendation accepted.
I have always had good results with Mobile One where I could use it only for the engine. Mobile One is not a good transmission oil because it doesn't have the sheer polimers necessary for transmission use. I use the Harley Formula + in the gearbox. I change my oil in engine and transmission oil every 2500 miles. The dealer does the change every 5000 miles per the service agreement.
Being in the car buisness I understand how service and warranty work. You are not required to use any special brand of oil as long as it meets manufactures recommendations. Diesel oil is in the owners manual. Dealers that say you must use the factory oil is not giving you the truth and using false pretences to try to get your buisness because they lack the ability or skill to secure your buisness.
If you never change your oil and your engine is full of sludge and has a failure they may try is say no warranty. They will loose in court because the jury always hate dealers and Harley customer service will help. You don't have to proove anything with reciepts because the motor will always show the truth.
The factory service schedule calls for oil changes every 5000 miles. Too long in my opinion but the book says so. I have said it before make friends with a good dealer and you will be fine. Everyone has an opinion and an a**hole. So crank it up forum. Another pint please.

Later,
P.S. No oil usage in first 1800 miles. So there!