I just got my 400ex on Saturday. At that point I didn't know that I was only getting 70% of the power from the bike, and I was still amazed. I beat my friend's 300ex, that is bored out to 360, with a whole new DG exhaust, K$N filter, custom airbox, better valves, and nicer plastic. He kept racing me (about 7 times), because he couldn't believe what he was seeing. every time, I won.
Today I found out that my quad wasn't getting the correct airflow (thx to this message board). I took it out for a test spin to witness a sustancial power increase.
My next objective is to beat my friend's warrior that is bored to 500cc. I don't know if I can do it. Look for this amazing warrior in the june or july issue of dirtwheels, along with his brothers 500cc walverine (travalina's). Just thought I'd share that info.
I am also looking for a rev limiter, can someone give me some info on this please!

Thanks, Chuck


'00 400ex (bone stock)

 

Good luck against the Warrior and congrats on the new found power...

At 500cc's, I would think unless the Warrior had some extensive porting and head work done, it would have serious trouble breathing at high R's. It should be a monster off the bottom though...

Let us know how it turns out!