Slip on exhaust? Need jetted?

I want to get a slip on exhaust for my 2002 yz250f... Not the header, just the silencer. Will I need to rejet if I put that on? I'm thinkin about an fmf but not sure which one. Currently have no issues with lean or rich running. Just want a better sound than stock.

You will not gain any performance. Decel popping will be worse. You will not have to change the jetting. Make sure you have no leaks If it is a used part, put in fresh packing. Change the packing every ten hours.

How will it cause more decel popping? It's not like I'm coasting without the clutch pulled in? The popping comes from the engine and valves so how would the silencer have anything to do without it? They'll all pop if you coast without a clutch... It's a race bike.... But again so I don't have to mess with my jets?

All bikes pop.
Aftermarket cans muffle less than OEM.

Therefore, with an aftermarket can, the pops will be more noticable.



Popping doees not happen because the clutch is pulled in. It happens when an engine is at high rpm/throttle closed. This prevents fuel from entering the engine but air does. Therefore a lean decel situation occurs., The unburned fuel accumulateds in the pipe and when enough is there, it burns with a 'pop'.


You do not have to rejet. An aftermarket can does not flow any different from the o\OEM one. It only muffles less effectively.

Oh ok I understand, see what I'm after is a littler better sound so it'll sound a little more modern instead of the old annoying crackle... My buddy has a 2011 and it sounds good stock but mine is nowhere near that sound and I just re packed my silencer 2 weeks ago

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