pipe change/jet change too?

[TYayo420]

ok i have a 400ex, i had a fmf slip on on it, and now i have a white bro's R4 full system.

do i need to re-jet?

if so what would you recomend for jetting? lid is on also.

and what about for lid off, how much of a difference in jetting would it make??

[j450rking]

you might have to.

i would say jump it up one jet size for taking the lid off

[GOTFEAR]

for sure at least 2 sizes on main maybe one clip

[EX LONERIDER]

place a new plug in it and take a reading after a short ride... see what it looks like and adjust from there. depending wether its leaner, richer, or if it even changed. my guess would be it flows better so id say richen it up. if you toss the lid, definatley up the main at least one size.

[CarGuy7a]

i'm running a 160DJ with the open lid. and with the stock lid it's just a hair rich. so i can run the same jet with the box open or closed.

the only difference is it runs rich on the bottom (idle to 1/2 throttle) with the lid on b/c i have a #40 pilot in it. my #40 at 1 3/4 turns out is good for the lid off and the #38 at 3 turns out is just right with it on.