sorry guys i just wanted you to look at my problem if i put jetting a 400ex would you have looked, i have just put a big gun exhaust full system on my 03 ex a k&n filter with outer wear do i take the air box lid off then re jet or leavr it on and re jet i live at about sea level what size jets to you think ,i have brought a dyno kit for it thanks again............

 

I'm not familiar with 400EXs, but I can tell you this: It depends on your riding. If you ride mud, you want your lid. If you're racing, you can do without it. I run without my lid, but it makes jetting trickier. I can't tell you specific sizes, but I also run a big gun system. They have recommended jet sizes, so call them and they can tell you. Or go online.

 

that was cruel[img]i/expressions/face-icon-small-mad.gif[/img]

 

Not answering, becaause you tricked me. Realy IMO I would just re-jet. Why go screwing with the airbox lid? It allows more foreign matter in there, not good! Unless you wanted to get two box lids, each for different riding conditions. Just my 2

 

I agree with Mrdumass, removing the lid is only asking for headaches,and the performance gain for 99% of us wont be noticable.

 

We have 2 400ex's at my house. If you come up with beer and naked stuff I'll help you out.[img]i/expressions/face-icon-small-wink.gif[/img]

 

Just kiddin'

If you ride in standing water more than not keep the lid. If you see a little puddle from time to time, throw the lid away. On our stock quad we have a dyno jet kit with a main size about DJ168 or so. That will vary from area to area but not alot. If you use the lid you will only want a DJ138 or so.

 

nice trick, got my attention (hope my girlfriend dont see this!!) lol

 

beer................
woman.................
naked..........................................
now im all screwed up and i wont be able to sleep tonight.
thanks.
but anyways.
im with the other guys if you ride in dusty or wet conditions you might want to keep the lid on but if you dont see any water or very much heavy dust try it without it.
you can always put it back on if you find its getting wet or to dirty to quick.
i dont think the performance gane will make that much of a differance unless your running against a clock or other people in a race.
i would keep the lid on less contamanents.