Replace nuts after exhaust install?

[Betlog]

Reading around here on the forums, people say to replace the retaining nuts that secure the exhaust to the engine.  Is this really necessary?  The shop manual calls for replacing the gaskets but not the nuts. 

[DoWorkSon]

Ive  removed and put back on my exhaust a few times and never had to replace anything

[WhiteStripe]

FWIW i didn't even replace the gaskets, just used liberal copper RTV.

[CRASH!]

+1 
I never worried about it and my pipes haven't fallen off yet...

[akmnstr]

These are self locking nuts.  I've replaced them after several disassembles of the exhaust.  They are exposed to a lot of heat and cooling and begin to decay.  I once tried non-locking stainless steel nuts.  They tended to back out and needed to be re-tightened often.  I'd say if they look bad replace them, if they still look good, use em again.

By the way, I'm talking about a bike I've had 11 years. 

[Howie]

GM actually has a chart for reusing self locking fasteners using torque wrench readings while running the fasteners down   Anyway, my opinion is if you got new ones, use them.  If not, as log as you feel more resistance than a normal nut when running it down, fine.  If not, either buy new ones (good auto parts stores should have them) or distort the end threads a little.

[ducatiz]

they are fairly common on the web.  i found a vintage porsche site that had them ("prevailing torque" copper exhaust nuts) for about 50 c each.

[Betlog]

How about doubling up on the nuts?  Keep the same copper nuts on there then use a set of stainless at the end of it.

[ducatiz]

Stainless will eventually rot