Motorcycle Repair: Twin Cam oiling issues, oil pumps, softail standard

Question
I have a 2000 Softail standard that has about 25,000 miles on it.It has A mikuni 42 carb, free flow air cleaner, performance exhaust,dyna 2000tc ignition, and a set of andrews tw37 cams that were installed over two years ago. The bike has been sitting in the garage for the last few months for the winter with only a few short rides here and there. The last ride was about 3 or 4 weeks ago. I changed the oil about two days ago. When I pulled the oil cap off I was baffled to see that it was really low. I wasn't sure why it was low just figured it was good that I had decided to change it. The one bad thing I did was to not warm up the bike prior to draining the oil. After I finish with the oil change I started the bike and let it run for a minute to check for leaks and everything seemed fine. Well the weather was good today so I decided to go for a short ride. Once the bike was warmed up I took off down the road. I had only gone a little over a block when I looked down and saw that the oil cap had blown off and there was probably a half a quart of oil all over the side and back of the bike. I turned around and went back home to check things out. I checked the oil tank and found that even after having all that oil all over my bike it was still over full (I only put 3 quarts in when I changed it), so I drained some more out. What I assume happened was that over the 3 or 4 weeks it sat some off the oil drained into the crankcase and then stayed there until I got out on the road again and then the pump tried to push all that extra oil back into the tank. I thought that Twin Cam engines/oil pumps were much better at not letting this happen? This has never happened to me before. What things would cause this and what might need to be done to keep this from happening? Thank you for any information that you can give.

Answer
Your tank sits higher than the oil pump, so some oil leaked past the check valve into the bottom end. When you changed the oil, you ended up overfilling it, due to the fact you didnt get all the oil out. When you change your oil always warm the bike up so that you can drain all the junk out.
To keep this from happening in the future, start the bike on a regulator basis and that will keep the oil out of the bottom end.
Good luck and happy riding
Mike