Some Black Sh@#$

[HondaRacing23]

I rode my 400ex for like 5 min and cam back and noticed black stuff all over the swing arm and where the header and silencer connect. what does that mean? To RICH probably! I have a K&N Jet kit in it and im thinking about taking it out and just going with what FMF Jetting guides say. can i still leave the jet kit Needle in or should i change that back to stock? I know that a jet kit will give me better throttle responce but will the keihn jets make any difference? Let me know guys. THanks:D

[hondarider2006]

You need the jet kit for the pipe and silencer, or your engine is going to burn up. It will be runing to lean. Also, I have the stock header with the wb slip-on, and where the silencer and header connect I had to put high temp silicon cause I had an exaust leak. Try putting some of that where the header pipe and silencer connect, that should prevent all of that carbon(black stuff) from getting everywhere, and it will make it run a little bit smoother.