Jetting question

[bonified5]

I just installed a power kit into my atv and I installed all the jets it told me to. I have stock exhaust and it came with a k&n. If I wanted to take the lid off the airbox, what jet would I have to change it to or would I be able to keep it the same?

[cals400ex]

with the dynojet kit, i would probably go up one size. i believe the smallest mainjet in the kit is a 142. heck, that may even be fine with the lid off. do the directions say anything about this?

[bonified5]

No they just tell u what jet to go to when you have an aftermarket exhaust.

[cals400ex]

go up one size from what they say to use in the stock format.

[400exhauck]

i have the same setup as you and i have a 165 in... it runs great... im only that high cause the directions said for my elevation (under 5000 ft) to use that one

[krt400ex]

my stock main is a 158. without an aftermarket pipe it's hardly going to help to jet it because, by removing the airbox lid, the engine will be getting more air than it can handle. at that point jetting won't help. if your stock main is a 158 like mine, I would put on a slip-on pipe and a K&N filter, remove the airbox lid(or drill some holes in it), and rejet to a 165 or 167.