First things first, here are some links to the KK2 flight controller Users Manual and Setup Guide.
Instruction Manual: http://www.hobbyking.com/hobbyking/s...30X7478X47.pdf
PI Tuning Guide: http://www.rcgroups.com/forums/showthread.php?t=1675613
Quadrocopter and Tricopter Info Mega Link Index
Here are the PI settings
I recommend as a staring point for frames ranging from 250mm to 600mm. I believe these are better than the stock settings that come pre-programmed in the KK2 board:
Pitch and Roll:
Low voltage Lipo Alarm Settings:
Stock numbers are 30. If the quad is too aggressive for you, reduce the numbers. Increase if you want more stick response. DO NOT attempt flips with the stock settings. You need at least 70 on ailerons and elevator to attempt flips. Try your first flips with lots of altitude!
Please note that in the pre-flight check video (part 4) below, I forgot to mention reversing channels as needed. This is explained in video "Part 6." Essentially, if your throttle channel or yaw channel is reversed, the board will not arm for you. If your throttle trim reads more than 0% throttle, the board will not arm, either.
Just go into the LCD menu on the KK2 board and scroll to "receiver test." If your channels are reverse you'll know right away. Reverse them in your radio.
Finally: DO NOT INSTALL PROPELLERS UNTIL YOU ARE FINISHED EVERYTHING SHOWN TO YOU IN THE VIDEOS BELOW.