The performance difference from stock to my new pipe is quite dramatic.More power everywhere,much more in the mid range and I havn't touched the jetting yet.Installation was quite frustrating though.

The headpipe wasn't bent quite right and was too long.It was hitting the airbox,had to put a pipe in it and bend it out slightly,then it was(is still) hitting the clutch cable.

Had to cut 3/4 inch off of the headpipe to get the rearmost mount bolt in.

It's the louder of the 2 types(Don't remember the model#)but it's not too excessivly loud.

While testing my new pipe I "got on it" in 3rd,wheels spinning and the left rear got traction on a rock,bike did a wheelie and made a right turn off the road into the bushes.Wouldn't do that with the stock pipe!

I believe that with some porting or cams this bike could beat a stock 400ex.

 

yah, invest in some heavier clutch springs thow. The more power you get the more the clutch goes away.