Ok!!! DO NOT get the 440 kit! It sucks...it gives the motor a shorter life span.

 

I know. Wasn't planning on getting the 440 kit. Thinking about gettin a 416 kit with a wiseco piston and stage II hotcam.

 

Ok, I just bought a 2003 400ex today. It is the fastest 4 wheeler I have ever been on! All it has is a full White Brothers E series exhaust, new pistons, new chains and sprockets and that's about it. It will fly! It will leave the KFX/Z/DVX in it's dust!

 

<div class="FTQUOTE"><begin quote>Originally posted by: 2003 400ex rider 911911

I'm 13 years old, you *******.</end quote></div>

Then put soap in your mouth! NOW

 

funny

 

Why are 13 and 14 yr old kids even on a 400? That's alittle big for some youngin's.

 

i have a 400ex with a 440 kit and yes it will give you more power but since the engine is heavier it looses its zip it will pull really hard off the line but then loose more of the high end... i would go with the 427 kit because you wont lose so much top end

 

ok thanks

 

We all did have to start somewhere. So to 400 ex (wich we have one and it is a good ride) keep riding keep trying and keep asking questions , you'll get there eventualy. But to answer your questions on the upgrades leave it alone and keep riding until you learn your machine top to bottom. Then go buy a real racer like a YFZ450 any year but for the best bang for your buck get a older one.Well thats all I got for you. God bless and full throtle.