pipe dent

It will effect performance more than anything. It is possible for a major dent to change the way the engine breathes and therefor it could change the air/fuel mixture, which could be bad.

A 1/4 inch deep dent is not anywhere close to what I would call a major dent, assuming it is in the fat part of the pipe. If you don't notice any significant power difference, continue to ride it. If you want to be on the safe side, throw a new spark plug in and then check the plug after a short ride to make sure the dent hasn't caused the mixture to lean out.

Wait until you get a second dent, then send the pipe out for repair.

Rod

This might be worth a read....

http://motocrossactionmag.com/Main/News/4413.aspx

Wow thanks for that link. I would have argued that one for a while It makes since on the head pipe and now I can see why some stock pipes have the upper expansion chamber dented in to clear things. the factory probably didn't see a change big enough to matter.

You can remove your own dents by filling your pipe with water and freezing it or a little air and heat. I have done lots this way