this sealant thing is just done much by guys with no or less money,
or understanding what they,re doing.
I'm trying not to be offended.... this was suggested by members of KXRiders with experience with the K5... not some broke redneck trying to avoid spending his beer money at the parts haus.
Pipes (especially aftermarket) dont always fit our bikes perfectly. I use the black RTV sealant along with (not INSTEAD OF) all the stock pieces for a better seal. It made a noticeable difference in the amount of black goo that was seeping out around the pipe and head. Besides, it peels right off when you need to remove and reinstall the pipe. If Kawi did everything perfect the first time then there would be a lot less to talk about here at KXRiders now wouldnt there? 
-G
my man Gdubb ..all 3 my bikes happen to have an aftermarket pipe

to be precise:
-FMF fatty
-DPR
-MILLET
none of them has the sealant applied ,i personaly simply don,t need it.
maybe this issue is more of a personal interpretation of how things are done

either way i didn,t want to hurt anyones feelings ,thats for sure.
ill stick to my approach ,will respect everyone elses methods

hughes has it right ,it is used often in older motors where guys didn,t do proper replacing ,
throughout it,s lifetime.
so if they did ..they wouldn,t have to grab some sealant imo .
@danger , that is not funny .....maybe that was a monday morning kx
freak