My stepbrother has an 02 400 ex, he's addeda wb e-series and a k/n filter. He never owned a 4stroke (has a banshee) and doesn't know what jets to use. Oh he also has a rev box as well. Any info would be appreciated.

 

The pilot should be 42 or 45. Main should also be 152 or 155. You will need to find out what works best for you. Of course you could also take it and get it jetted if cost isn't an issue.

 

Oh I also forgot that he has his cammed up too. If you can help that would be great. Thanks.

 

a 155 main jet should work fine as long as you are not at an extreme elevation.i would also like to recommend that you contact(www. powroll.com) and inquire about their vented air box lid for a 400 ex it really helps that motor breathe.

 

<FONT face=Myriad-Roman size=2>
This if from the White Brothers website....... I can tell you its REAL close.

"This particular model ran best overall when using 12 E-Series Discs. The system is provided with 12 Discs, whichprovides an excellent base between power, sound, and running the stock jetting. When running up to the maximumof 18 Discs, horsepower went up in the mid & top-end range (as shown on the dyno graph above), along with thesound level. Also, when running with the airbox lid off, the horsepower also increased. You could also modify the air-boxwith "air vents/filters " (WB # 46-509). It ran slightly lean (carburation) on this particular model and required a 165main jet (when using 18 Discs and the airbox lid removed). The stock main jet on this particular model was a 155. We have seen main jets from 142 through 148 on other TRX400’s. If you decide to use more discs (over 12) and/or remove the airbox lid or modify the airbox, you should start with from 2 to 4 sizes larger on the main jet."</FONT><B><I><FONT face=Myriad-BoldItalic color=#ffffff size=2>
DYNO GRAPH FOR HONDA TRX400EX</B></I></FONT><FONT face=BankGothicBT-Medium size=1>
5</FONT>

 

Tanks for the info guy's. My stepbrother is going to get some jets today.

 

I run a white bros e-series with no lid and an outerwear. I have a 155 main and a 40 pilot but I was still getting let off backfire until I adjusted the needle one notch richer.