I have a 2000 WR400 that I bought new and love the bike. I have almost 9K miles on it with no problems whatsoever, (mostly mean single track) I presently have a White Bros tapered head pipe and E series muffler. I have restuffed the muffler and installed a quiet core insert, but it is still too loud, (98db) but I love the power it makes. Other mods are YZ timing, gray wire, etc, etc. I really hate to remove the exhaust for something quieter, but I guess it is a sign of the times. Sure would like to keep the White Bros. tapered head pipe. Any suggestions???