Stock exhaust question

[Philippe1985]

I know that an aftermarket exhaust system needs new damping material from time to time. But for a stock exhaust, which hasn't got that, does it downgrade too? And in what way? Because my bike has now 20000km and it is really louder and deeper at iddle. There are no gas leaks. Or could it be the katalysator that becomes older? It started just before my last service. The bike has had all service in a Yamaha dealer. Thanks for reactions.

 

[stink989]

It will become louder as it gets older. Have seen a few FJRs with over 100,000km and it sounds like they have a set of staintunes on!

 

[Philippe1985]

And why do they become louder? The reflection chambers stay in place so...

 

[RJ2112]

Any muffler relies on packing material to absorb some of the sound energy passing over it. OEM designs fold the exhaust gas flow back and forth to increase the time the packing material can act on the sound. The material still 'packs down' due to impurities, just not as fast as the straight through flow of after market designs. There's 2-3 times more packing material to foul.

 

[Pimpson]

I'm almost positive that the stock muffler contains no packing at all. Similiar to a flowmaster.

 

[RJ2112]

I've seen photos of OEM mufflers that have been cut open to remove the baffles.... looks like the walls are multi layer to me.

 

[bike10]

i posted pics of my gutted stock muffler about two years ago, no packing.