hi guys, just bought a 2006 yz450 muffler for my 2009 wr450. Muffler fits perfect except the muffler pipe is too big to for the stock header. the clamp does not tighten the muffler pipe enough to create a seal on the header. when i start the bike air blows out where the muffler and header meet. does anyone have any suggestions apart from buying a new header on how i can seal this gap?