does a quad need jeted just to have a k&n air filter on it mine didnt but my friend thinks they need jeted he just got it jeted a week ago for his slip on exaust and now got a k&n air filter and needs to know if it needs rejeted

 

No

 

Actually, yes. The K&n gives more flow. Anyways, try checking the plug. If you don't know how to jet, get help from someone that does. I had to jet my 300ex up a couple sizes after adding a K&N. With an exhaust, K&N and no air box lid, I went from a 122 main to a 142, and it is still slightlty lean.

 

Yes it does. If you run it without rejeting you will most likely be running lean.

 

I've installed K&Ns on my last six quads. The airflow difference wasn't enough to require a jetting change.

 

Well, then you must be special, because most of us have had to rejet.
Don't plat guessing games, check the plug and see if you need it.

 

Well, if you don't have to rejett with the k&n filter that just proves my theory that, K&N filters don't do $hit.

No jetting required = no performance gains

 

Brocksz, Maybe, maybe not.
If your exhaust is restrictive, then doing any thing to the front side (jets and /or filter), wont help a thing.
Just putting on a filter or pipe or jetting alone, wont get you much.
If you do all three, then youll see alot of improvement.
If you improve the breathing...most likely youll need to improve the exit (exhaust).

 

Thats not true. If you leave your exhaust stock and take your airbox lid off it will make a difference, right? My point is, I think a K&N air filter is a waste of money. The unis and twins are just as good if not better and cost less.

 

pretty much if u do oone u gotta do the other. just putting a filter on isnt gonna help cause u still dont have enough air going to it anyways.but if u take airbox lid off and then it will have to be jetted.for the best results which u all no is to put airfilter and exhuast on at the same time