Can you gain more HP by removing the baffle out of your stock exhaust pipe on an 06 YFZ 450.. I also want to know if you there is anything specific you can do to modify your stock pipe to get a little more hp out of the bike....

And does my 450 have to have any kind of back pressure and the reason i ask is if i remove the baffle will it hurt the engine...

 

You will gain a little HP by removing the baffle. It will also lean out the engine a little due to the loss of back pressure so keep a eye on the plug. If the tip turns white than you are running too lean

 

does loss of backpressure hurt the engine?

 

Loss of backpressure is not a problem, but you will likely have to rejet to conpensate. My NMotion is pretty much a straight through design, little to no back pressure.

As far as modifying your stock pipe, you can either use the "hole saw" method and cut a circle out of the baffle in the pipe, or cut about 6" out of the center of it and turn it into a shorty. I started the shorty method after I got my NMotion, but never got around to finishing it.

from the process:




The way I had it set up, I would use the rear mounting flange on the muffler to bolt onto the front location on the frame, and after cutting the center out, the new welnd would be "on top" of the original weld to give it a somewhat clean look.