Any day now, I'll be getting a new FMF exhaust system for my Warrior. I just put in a K&N replacement filter, and I plan on carving a huge hole out of the airbox lid. Will the FMF exhaust come with a jetting guide? Will it also take into account aftermarket air filters? If not, do any of you have any suggestions for how to correctly set my jetting, needle clip position, and mixture screw? All of this is new to me, and I would appreciate your help. Thanks.

 

I got a 2000 Warrior.Supertrapp IDS 2 pipe,Pro-Design filter w/adapter,and my settings are as follows.150 jet from Dynojet jet kit,factory position on my needle,and factory position on my mixture screw which is 2 turns out.I am plannin on gettin a aftermarket lid also.

 

I wasn't aware that FMF was making a header for Warriors since the stock head pipe is so large to begin with. Rather than the "huge hole" you mention in your air box, why not consider a vented lid from Moto Force? You'd have 90% of the air flow of an open air box(according to the tech at Moto Force)plus having the protection against water entry of a lid. Also the number of discs you plan to run in your silencer will have a bearing on your main jetting.
Your pipe will possibly have suggestions as to the main jet increase, but only suggestions due to the variation in elev. at buyer's locations, and cannot know of other airflow improvements you make.
If you plan to open up your air box in any way,I'd suggest you pick up two Mikuni main jets, a 150 & a 155. try the 155 first in a test ride/plug read. If the plug is a little black you can always drop down to the 150. Always better to err on the side of rich than lean.
Swain is correct on the jet needle. It should be in the 3rd position & the pilot screw about 2 turns out from seated.I run a 155 in my quad at 3200'elev. If you're lower than that, it may be right for you too.

 

Yeah, I bought the new header, then took the old one off, and when I saw how large it already was, I thought, "wow, I wonder if I shouldn't have bought that FMF pipe?" Oh well. I didn't by the megaphone silencer with discs. I bought the PowerCore Silencer. It's just a straight shot out the back. But anyway, thanks for the input, I appreciate it.

 

Glad to help a fellow Warrior owner! lol