Repacking Mufflers?

[Elk]

This is prompted by wanting to learn, not by any issue.

When do motorcycle mufflers need to be repacked?  How do you know it is time? 

Thanks!

[Greg]

I've ridden 3 mufflers to 40k each and didn't repack one. They may have needed to, but I never noticed an issue with power or noise.

[Mike Duluth]

Where would you even buy packing for a muffler?

[Elk]

It is regularly available, and some manufacturers even provide kits.  This is one of the things that made me curious.

I have never repacked a car or bike muffler, have never noticed an issue or change, have never seen hot spots on the muffler indicating a problem inside, etc.  Thus I am curious if this is a real world issue, only for the fussy, or limited to a racer's concern where sustained high RPM full throttle produces a difference environment and is hard on mufflers.

[naustin]

I *think* the factory mufflers on my ST-1300 are designed with various baffles that split and route exhaust and sound in different internal paths such that there is no packing in the first place.  They also have integrated cats, which in and of themselves result in quite a bit of silencing.  They definetly are sealed, and there is no way to open them up anyway...

All that to say: not all mufflers have packing.

[GUZZI JOHN]

 I'm curious as to what bike you have w packable exhaust. Most likely aftermarket as I don't recall packing being used since the 2 stroke days.

[vince]

I have Kerker exhaust system and you have to repack the muffler.