First off, I will never answer "do you know why I pulled you over" with anything other than NO. The officer knows why they pulled you over. There is no reason to offer up a reason to the officer, make them tell you. If you get pulled over for speeding but offer up that you forgot to signal when changing lanes, you just admitted to another traffic violation.

As far as what to do, birchboy suggested exactly what I have done in the past. Turn the bike off, put the kickstand down to show you aren't going anywhere as soon as the officer steps out of the car, and keep your hands out of your pockets, tank/tail bag, or backpack. I keep my hands on the tank until I am asked to provide something and then I will tell the officer exactly where my hands are going to retrieve the license/registration/insurance. No reason to make the officer more nervous by moving around a lot and putting your hands where they can't be seen.

Be POLITE. You won't ever improve your situation on the side of the road by being disrespectful or arguing regardless of the attitude of the officer.