WHAT'S INSIDE THE WELDED PART OF THE 2009 HONDA MUFFLER? THE ANSWER? THE HONDA CRF450 RESONANCE CHAMBER
Dear MXA,
What is in the welded chamber in front of the CRF450 muffler? Does packing go in there or is it some kind of megaphone?
It is neither. It is a resonance chamber. The midpipe extends through the chamber, but has four 12mm fours drilled in it to allow exhaust pressure to bleed off. The chamber is empty. It reportedly lowers the sound level by one decibel, but when added to the 2009 CRF450’s very short muffler it does not add up to an AMA-legal muffler. It tests at 97dB.
IF YOU HAVE A QUESTION FOR THE MXperts, send it to mxa@hi-torque.com

Honda Motorcycle tests