I just got my wife a 2002 400EX and it's stock but it has a foam filter. I hate foams. I run K&N in the DS and want to put a K&N in the EX also simply to keep it the same and cleaning. I can almost bet we wont be suping hers.. So, am I fine with the curent jetting from the factory... Lid and everything will stay on...

 

Honda jets lean at the factory. Even a little more air might push it to far?????

 

Could I just get away with moving the needle up? the main only works on the WOT anyways....... What is the stock filter? I wonder if what I have is stock, I highly doubt it..
Even with the lid on it will flow enough air to require jetting?

 

U could do a plug check and see if its running lean?

 

you may want to go up on the mainjet from a 148 to a 150. in the middle of summer, the 148 should work fine. in winter, when the air is more dense, a 150 might be better. i would leave the needle in the factory position and turn the fuel skrew out 3 to 3.5 turns from it being lightly seated.

 

hey cals400ex, are you sure thats right about the jetting during summer and winter? i know that on my uncles pullin truck we richin the carb up as the weather gets cooler, if we dont the headers will glow because it runnin to lean. anyhow, i think it is supposed to be more fuel during winter and less during summer. nathan