400ex Air Filters

[jelliott]

i am having a hard time on picking what air filter to get.. which one would you guys suggest? i looked at a sparks filter and a uni filter but out of all of them which one would be the best? i have a stock engine, i have a e series slip on and i am about to take out the choke. thanks

[derek07]

i have a K&N filter and it works very good

[jelliott]

well i can get a uni for like 25$ plus shipping, a Sparks that comes with the alum ring for 45$ plus shipping, or i can get a k and n for like 55$ plus shipping or i could get a twin air for like 23$ i dunno which one to get

[Steve-o 400EX]

i would recommend a foam filter over a k&N, I have a sparks and am pretty happy with it, i would also recommend UNI. Foam filters will screen much more dirt than a K&N will. I know this because my buddy and I have very similar motor setups and he runs a k&N and his oil is like 5X's more dirty than mine. Just stating what i know.

[Florida400EX]

I run a Twin Air with no problems, they are all pretty much the same between UNI, and Twin Air, both are the two leading filter companies in the MX scene.

[jelliott]

ok thanks for the info! i am debating over a uni or a sparks or twin air now.. if i road track all the time i would choose a k and n but i dont so i am either goin with uni, sparks, or twin air thanks for the replys

i was wondering how much diff can you tell with your choke out of the carb? i took one out of my friends 300ex he said he could tell a big diff

[cals400ex]

i would get the uni. the twin air is quite a bit smaller than the uni and also with the uni you loose that stock metal cage which could be somwhat restrictive. the sparks is just priced too high for my liking.

[b400ex]

K&N is the way to go

[JR3]

yea k and n i run 1 with a vented lid and a outwear on the filter

[khen]

I switched back from a K&N to the stock filter. My K&N w/outwear plugged up to quickly and I found grit in my intake. I didn't notice a power difference going back to the stock one and it's filtering much better. When it wears out or I do some engine mods I'll be buying a UNI.

[jelliott]

thanks for all the replys guys! i think i am goin to go with the uni,, you guys think i should change my jetting after i take out the choke and put the filter on? i still have the stock 148 jet in it.

[cals400ex]

Originally posted by jelliott
thanks for all the replys guys! i think i am goin to go with the uni,, you guys think i should change my jetting after i take out the choke and put the filter on? i still have the stock 148 jet in it.


if you have a slip on, yes you need to change your jetting. going up a few sizes on the mainjet should be good. you may want to put in a 42 pilot jet for easier starting too.

[jelliott]

alright you think a 155 main would be good? sometimes i alternate between stock and e series because its loud and my step dad doesnt wanna hear it all the time lol what does a 400 carb have in it for the pilot from stock?

[plkmonster2]

The stock pilot is a 38. I'm getting a 42 so it starts easier. (Getting harder as the weather starts to get cold!) It's a good invested for 3.75 from C&D! A 152 main should suit you well if you switch back and forth. I run a 155 with uni filter and hmf pipe, but I ride from sea level to 1500 feet. (Thicker air=more oxygen)

[DaleJrFan]

k&n all the way, you can buy a recharge kit for ten bucks and your set for a long time