*** Aftermarket exhaust question ***

[bkvette3]

Hello all.

I am contemplating a FMF pipe and Powercore silencer for my '85 ATC250R. Stock - no mods done to the motor. Will there be any noticeable difference??? Is re-jetting necessary??? Your opinions/suggestions greatly appreciated.

Regards BK3

[crackshot]

I have a bill's expansion chamber and a turbine core silencer on mine. Yes you will notice a bit of a difference. Mine is stock also and have a uni filter in air box. You should do a plug chop to check your jetting.

[bkvette3]

I have a bill's expansion chamber and a turbine core silencer on mine. Yes you will notice a bit of a difference. Mine is stock also and have a uni filter in air box. You should do a plug chop to check your jetting.

Thanks crackshot. School me here, brother, what is exactly a "plug chop". Sorry for being stupid - never heard of the term.

[crackshot]

This might explain it pretty good.
http://www.dfn.com/agservices/plugchop.html

[bkvette3]

This might explain it pretty good.
http://www.dfn.com/agservices/plugchop.html

Thank - you, sir. Now I know.

[tri again]

I've heard stories about jetting many times over weeks to get back in balance with a new exhaust.
Maybe more of a problem with 4 strokes but not sure.
I'm more of a stock exhaust kinda guy because of the forest service approved
spark arrest feature.
You MAY need a handful of sequential numbered jets to get it dialed in,
then again, it may work perfectly. Just a thought.
Are 2 strokes more picky about mixture? Wish I knew more.