need help with Pilot jet!!!

[BassGin3]

I have a 2001 400ex and it's stock for now, but i just got a full big gun race exhaust and k&n filter with outerwear. what i was wondering is if i'd have to change the pilot jet or if i could get away with just playing with the idle screw. I called the dealer and for a 40 series pilot jet it would be $13, nothing too much but is it worth it? I have a 158 main jet for it and plan on raising the needle clip up one position when i put it all on. Also seeing if anyone has a similar set up and if they run with the airbox lid on and what kinda power they see out of these mod's.

[Silverfox@C&DRacing]

If it doesn't backfire on deceleration then you won't need a bigger pilot, but if it does backfire you can turn the fuel screw out 3 1/2-4 turns to see if this helps. if it doesn't you need a bigger pilot around a 40 or 42 we sell them for $3.75 each.

[chrisp333]

you neede to go down one notch on the needle not up one...

[cals400ex]

yeah, try turning the fuel skrew out. for the big gun slip on, K&N filter, and outerwear and the elevation here is about 625 feet: the bike performed the best in the summer with a 152 and in the winter with a 155. good luck

[BassGin3]

thanks guys

[300exOH]

I'd listen to Silverfox. She knows her stuff!