I think I already did. Apparently the smiley face did not convey that I was kidding with you.
They run rich for the first little while and when you let off the throttle it will let a little gas into the cylinder that some times is not ignited. Next revolution of the crank and bang. As the motor gets a bit broken in this will let up. As I mentioned, a hotter plug like the champion #8 or better the NGK Irridium will help out a bit as it more fully burns the fuel it seems, can be of help.
That being said it will go away on its own. Just try to avoid hard on the throttle to none at all and you should be good.
Welcome to the forum, its a great place and you have a great quad. I know cuz I have two.