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View Full Version : Stock air filter



2001 trx400ex
04-16-2003, 04:17 PM
Has anyone taken out the metal core inside the stock filter and ran it with just the foam. I had a K$N but i sold it cuz i didnt like it. I put the stock on with the core out and i didnt find any difference in performance.

Sportrax10
04-16-2003, 04:24 PM
I think thats just for keeping the foam sturdy. It probably dosnt restrict enough air to add performance when you take it out.

2001 trx400ex
04-16-2003, 04:26 PM
y did i notice 0 difference between a stock air filter and a K&N. K$N says they give 2 more horsepower. I got a pipe rev kit and hotcam stage 1 and no choke. I didnt notice any difference. jets r 165 main and 45 pilot.

400extracc
04-16-2003, 05:51 PM
u say'n u have a pipe, cam, filter, and no choke and u feel nothing. whats up with that??? all i have is a t-4 slip on pipe stock filter with air box mods. and jetting, i feel a difference. a pritty good difference. its all in the jetting man. wrong jetting u'r quad will run like crap. just from what i have noticed with poor jetting.:macho

2001 trx400ex
04-17-2003, 05:53 PM
i didnt notice any difference when swapping the stock filter wth the K&N

2001 trx400ex
04-17-2003, 06:07 PM
help please, is this good or bad to do.