I am going to get a 2003 400ex now that my blaster sold and honda has some good deals on finiancing. So i am going for it!

Well first, after break in i want to get a Pipe, Jet Kit, and a new air filter.

I want mainly low and mid range power. What pipe is best for this? I am looking mainly at a Curtis Sparks, but at 489 thats pricey! What about White Brothers? CT racing? Big Gun?

Any suggestions are welcome

 

I just went down to a 14 tooth front chain sprocket on my 400. It gave me what I wanted for trail riding and was easy to change. Try that first and see if that helps you to get what you want. Plus it is also cheap and you can allways go back to the 15 tooth if you don't like it.

 

Just about every pipe will give good power down low and in the mid-range (3500 -6000 rpm), but don't expect Raptor like numbers on the top end. You will only get about 1 more useable horsepower out of the two best pipes (White Brothers E-Series and the CT Racing).

 

it also helps to put the shocks on the softest preload settings, and only run about 3 lbs. in the tires
makes for a much more comfortable (plush) ride on the bumpy trails
I'd just remove the spark arrestor, trim both ends of the snorkel, and up the main jet a size or two if you want to keep it quiet on the trails

 

DSAPP,

Is the spark arrestor removable, not just for cleaning, but for running? How much louder does it make the machine? Since we are in about the same area (geographically speaking), what main jet are you running? I'm looking to get a 40 pilot jet for mine along with what ever main jet you suggest. I just need a little more low end (ordered the 14 tooth front sprocket).

Thanks!

 

With the design of the silencer, removing the spark arrestor does little more than give the exhaust not only a louder tone, but a nasty sound as well. The bulk of the restriction in the stock exhaust is within the silencer body iteself.

If you want a quiet, but more free flowing exhaust, drill a 1 - 1.5" hole in the rear wall of the silencer body (when looking in with the spark arrestor removed). This will straighten the exhaust path and make an improvement in the bottom and mid while only increasing noise output a small amount.

Be careful only running 3psi in the tires - while it does make for a very plush ride, if you are an aggressive rider it will make you a lot more likely to pinch the tire and end up with a nasty sidewall puncture.

The 14T front sprocket is a nice add-on to a stock 400EX used on the trails - if perform any mods, go back to a 15T or even a 16T if you do very much.

A 42 pilot works well for most stock carbs and setups - makes the quad start easier as well.