Maybe your crank seal is bad and primary oil is getting into your engine...NOT! Just kidding. Your engine cannot have more oil than was put in it.
The true reading if your oil level is when you turn off the engine and remove the seat and check it. If it reads over full, it is overfull. drain some out. I've been known to use a turkey baster and tubing to pull a bit out to get it right. Then ride it again and check it again until it reads consistently. Then you know the correct amount of oil is in your engine. Alternately, change the oil and add 3 quarts. Ride until hot, check it again and top off if needed.
There are a couple of ways in which oil can leak back down into the sump, and if the bike has been sitting and the oil leaks down into the sump. Usually the bike has been sitting and since you are careful you check the oil. If it reads low on the dipstick, you add oil until the dipstick reads 'full'.
When you start the engine, the oil pump does two things:1. It pumps oil immediately to the upper engine, then to the crank, etc. 2. The other side of the oil pump------yes, these oil pumps are really two oil pumps--supply (high pressure) side pumps oil to the engine to lubricate it, and the return side (high volume) sends the oil to the filter, then back to the reservoir in front of your rear wheel. So if oil seeped into the sump and (and was hiding from you) and you added more to please your dipstick----Voila! too much oil in the engine (not good).
So..back to WHEN to check your oil: do it immediately after riding. Remember you are not checking the oil in the engine...you are checking the oil in the reservoir...there's not supposed to be more than a few ounces of oil in the sump, but if it leaks down, there can be almost a quart down there. I do not think this is damaging to your engine bcs the return side of the oil pump immediately gets busy sending oil from the sump back to the reservoir, and the tank will not ever have any less than two quarts in it available to lubricate the engine (unless an internal standpipe is broken).
The most usual culprit would be the check valve. That is the inside cap on top of your oil pump...it has a spring under the cap with a ball bearing remove the cap and the spring and remove the ball bearing. Turn the motorcycle upside down and it will fall out, alternately use a small telescoping magnet. It's best to do this when you're changing oil, so you can look in there and see the lower ring (the deeper ring is when the bearing fits), and oil won't be seeping out all over the place. Inspect for debris and clean as necessary. To re-seat it, drop the bearing in and use a small punch with a flat face, and tap the top of the bearing soundly it with a brass mallet. You want the bearing form itself into the aluminum. Then remove that ball bearing and replace it, as tour violence might leave one side of it flattened or scored.
I didn't realize until recently that our oil filters also have a check valve to prevent oil from back washing through the filter. The oil comes into the filter around the sides and is pumped through the middle back to the reservoir. So inspect the check valve in the middle of the oil filter (or replace it).
I also think a check valve seat problem is usually slow acting, in that it takes hours or days to seep a measurable amount of oil past that ball bearing. Of course hot oil flows faster, and if a piece of debris keeps the bearing from seating it will leak faster.
p.s. ask how I learned about this particular problem....and I hope some of the guys who are much more knowledgable than me will add to this...I have been fighting this with my 08 K9 for a while now..currently re-doing my oil pump (not needed, but I had to know if the gears were ok). I am also suspecting that this is a more common issue than is apparent. Lots of guys talk about overfilled oil tanks.
