nebody else's pipe do this?

[muddy400EX]

whenevere i run my HMF without the spark aresstor i turn it off and smoke rolls out the cap for 2-3 minutes. is this bad or is it just cuz there isnt a s/a in it? i usually run with it in but im just wondering

[TRAIL]

Mine does it sometimes but i only have one short ride on my pipe.....

[LazeR]

is it brand new ? if so its the packing i think. Mine did it when it was brand new and it had a weird smell.