I don't like loud exhaust so what is the quiet one that is close to stock that I could put on it? And if you have one how do you like it? I have a 2000 400ex...thx Jeff

 

If you want quiet, stay with the stock exhaust.
Any after market exhaust is going to be quite a bit loader than stock.
Honda's stock mufflers are pretty good as for as performance is concerned.
You can look on eBay for a larger exhaust tip. search 400ex exhaust tip.
This will increase performance slightly while still using the stock muffler.
You will need to rejet.

 

thx dude that is what I am going to do. I don't like the loud ones and I think the new tip with my new uni filter is going to work just fine. what size jets are people running with this set up?

 

depends on your altitude above sea level and performance mods.