Hi guys . I am new to the hobby and recently brought a quadcopter from RcBazzar.com.http://www.rcbazaar.com/product.aspx?productid=4571.  I finished putting it together and charged the batteries. I got a new flight controller the KK 2.1 The TX is avionics RCB 7i. Batteries are 3c, 11.1v wolfpack 2200mAh . I did all the calibration and ESC calibrations.  I checked all the controls on the screen of the KK2.1 Every thing was OK. After checking the gyro bubble I armed it and tried to fly. I also set the trims to 0. As I was flying Indoor i couldn't give more throttle. But with the little throttle that I gave it started going to one side even before taking off. I tried adjusting the PI values according to the manual but to no avail . I tried turning the self leaving on and off but also no use. I calibrated the whole thing many times but no change. I will go out side and try to give a little bit more throttle and see if I can correct the movements in flight. Plz as i am a newbie any suggestions are welcome. Thanks in advance. If needed I will post a video showing the quad.

Put it in self leveling mode and take it off the ground... There is quite a lot of resistance near the ground so it tends to drift.
Just go outside, take it up a considerable height and see.
And the copter is not going to stay perfectly stable until you have a gps system on the flight controller. You will have to keep correcting it.....
Happy flying

Almost every beginner faces this tilting problem. Sometimes its the wrong rotors in wrong positions or the wrong motors in wrong positions. Even incorrect direction of the controller. In my case, it was ESC cables going into the wrong pins of the flight controller's output. I don't have any idea about the KK board as I built one with APM but

Tilting/ flipping is a problem almost every newbie has to go thro'. There is a simple test i read elsewhere on net and use it to test every new build.

Arm and apply throttle so props are spinning fast but craft doesn't take off. Move roll stick to left the right side should lift slightly, move roll stick to left the right side should lift slightly, similarly you can check pitch by moving sticks slowly to front and back the back or front should lift properly. If this works then your motor and prop orientation is correct.

I suggest you use default PID's in beginning don't change them till you have a lift off and some familiarity with flying it.

Most of the time the problem has been wrong motor direction or wrong prop mounting, if both these are correct the order of motor wired to FC may be wrong. There may be other problems but these are most common.

KK2.1 is a good beginner FC an can fly almost anything as long as wiring and direction of motors and props is correct.

Good luck...