yamaha uses that on the banshee.

 

Yeah the banshee airbox blows.I have owned a banshee for 9 years.But I have never installed the filter the wrong way and let dirt into motor.If you cant do something as simple as putting an air filter on a quad let the dealer do it.Although they will probably screw it up too.If all you are doing is going from stock filter to k+n no way will it blow up.Probably wont even have to change jetting.If you take lid off box or put a new muffler on it you will have to richen jetting a couple sizes.

 

I remember reading it somewhere but forgot which way do you move the needle to richen it. is it hard to do. What is stock main jet for a 300ex

 

didnt have to rejet my recon after i put a K&N on the plug was tan after it
hmmm www.atvparts.com i think the K&N there is 19.99 if i remember right i gotta order one for my 250X