Just wondering if the air boxes had the same size opening. Or if anyone has tried putting a 400ex air filter in a 250x/300ex. Any info would be great thanks.

 

why do wou want a 400EX airbox to fit a 300EX?

 

LOL no i wrote the filter from a 400ex. I want to put a 400ex filter in my 300ex cause i need more air flow for this modified motor. I already have a 350x atc intake tube coming along with a bigger carb. I would like to put an air filter that breathes a lil better in. I was wondering if anyone has tried putting the air filter from a 400ex in a 300ex airbox.

 

lol Wondering the same thing.......

 

Oh sorry i didnt see that msg up there. Im not real sure they probably do match. I might have a 400 air filter laying around here somewhere ill check and get back with you.

 

Go w/ a K&N thats what I run in my 300ex w/ mods [img]i/expressions/face-icon-small-smile.gif[/img] but I think they do fit, if I remember right the 300/400 K&N's are the same?

 

I haven't owned a 300 in many years, but as I recall I had White Bros. Powerfilters back in the day, and they were the same for both the EX's. Try going to UNI's web site, and see if the two bikes have the same part number.

I would avoid the stock filter, and that ridiculous screen insert that goes with it. Just get a UNI and you will be set. I don't trust K&N!!!

 

YEP UNI's are good to [img]i/expressions/face-icon-small-happy.gif[/img] we run one on our blaster w/ NO airbox & have NEVER had a problem w/ it!! As for the reliability of the K&N you really have to watch the oiling [img]i/expressions/face-icon-small-smile.gif[/img] I haven't had any probs w/ mine on my 300 & I never run a lid except for the deep water/mud rides [img]i/expressions/face-icon-small-wink.gif[/img]

 

I dunno if the k&n filters have the same part number. But i do know that the uni filters have slightly diff part #'s. the 300ex is 4109 and the 400ex is 4129. reason i want the 400ex air filter is because its twice the size. My modified engine is starving for air. I already orderd a bigger carb and some other things to help it breath better. And i have a uni filter now. I would never use a k&n filter in my quad. I do have them in all my cars and trucks though.

 

no they r different the 400 ex has a duel inlet and the 300 is a single inlet i have a 300 and my buddy has a 400 but he did buy it used so it might have been modded but i dought it. but u can drill some holes and get air box plugs they are like $10 for 10 of them u just drill like a 5/8 or 3/4 hole and then pop these in and boom more air. would not sugest running no lid gets to much dirt in and then engine kabloomy. good luck