I'm almost under the impression you may really never need to add oil to ours unless there is a problem or riding under extreme conditions. I do agree over filling oil is a no no!
so you are just "almost" what gives you just an impression? .
I am saying that you do not need to ADD oil to your motor every time you see the dipstick read something less than full. most of the time either we are reading it wrong or the stick is showing it wrong. you could re read the dipstick 2 or 3 times in a row and get 2 or 3 different level readings. So? even if you had just 3 qts in your pan, do you think the motor is starving for lubrication?
I would offer to say that at any given time only 1 quart is actually in circulation while the rest is sitting in the pan waiting its turn thru the pump and around the block.
IF you found your reading to be all the way on the low mark, Probably only because you are riding hard and/or at speed such as when you travel on Interstates, you might be "consuming" oil as in blowing vapors into the airbox. THEN you should add a full quart / top off only because you are traveling. IF I found this to be the case and I was either near finished or not traveling, I would just change the oil and filter and start new.
I would measure how much came out. Something less than a full 4qt charge? This is how I read how my motors are behaving. What kind of oil consumption do they use (zero) , what kind of mileage does it get - is it varying any? and why? are there any performance issues that need looking after? Air Filter all clogged up with too much oil vapor and accompanying dust? spark plugs, I used to check them for color and gap. it would tell me how the motor is doing or if I needed to pay attention to something.
I suspect there are fellas that beat on their machines and ride them pretty hard. They may consume more oil, gas, tires, etc than the average bear. ok, so maybe they need to stay on top of their shenanigans and keep their motor overly lubricated as opposed to ever running it dry. If you are going to play hard will then you should play safe. poncho