just got an oil test done on my bike to see if i could go longer on an oil change. just motor oil and filter was $61 last time. I have an 03 ultra, 48,000 miles. amsoil 20w/50 at 2500 miles. had it done by Blackstone labs and this is what they said: " Clearly this oil is working well in your Harley. Universal averages show typical Twin Cam 88 wear after an oil run of 3,900 miles. You ran this oil just 2,500 miles and your wear is lower than average, just like it should be. The oil was in good shape physically, containing no moisture, fuel, or other contaminants. The air and oil filters (silicon and insolubles) are working well too. And the TBN read strong at 6.6, so more miles will be fine. Try 3,500 miles next. Nice!" food for thought for anyone else wondering how long to do oil changes. I know this can be a big debate and I know milage is all depending on how you ride. my 2500 miles was not all highway. it took me 5 months to get that and I ride frequently. safe riding!