I am contemplating buying a 400ex or a 450r, but dont like the price tag on the 450r or the need for alot more maintainence. I have an atc 350x and a 250r and would like something that is in the middle. I dont want a 4 wheeled 350x, i.e. a stock slow 400ex. Is there some decent mods i can do, such as jetting, air filters, air box lid removal and a pipe to make it somewhat close to a 250r's power. I dont want to get into the motor. I dont plan on racing it but i want a little more power than that of my 350x which is rated at 28 horsepower. Something like 35 horse power would be cool but thats probably dreaming, without getting into the motor.

 

To get that much HP you will need to 440 it.

 

I was getting smoked until I did the 440 kit now I run very well with 250r's

 

what would a pipe, and a k&n power up kit do for me?

 

2-3 horse would be pusing it...

 

I didnt clarify but i meant competitive with a stock 250r not a fully worked one. What is stock hp of a 400ex, 30?

 

the stock 400ex have 30 h.p at 7000 rpm

 

i have a 2001 400 ex fmf full exaust kn filter no airbox dyno jet kit . was able to keep up with lt 250r on a track stock motor whitebrothers rev limiter.