Going back to stock exhaust.. why?

I have a 2008 WR450F with an aftermarket GYTR exhaust with GYTR jetting.

The airbox mod has been performed on this machine (top of airbox removed for greater airflow) and it has the stock header pipe.


The GYTR exhaust is offensively loud! this thing gives me a headache.


If I place the old exhaust back in (which is practically silent) must I rejet? or it unnecessary because the airbox mod remains?

If I rejet back to stock I am worried I will be lean because of the extra air intake.


You might be a little rich. Don't worry about it. Ride it and respond to any rich spots with the next leaner jet for the operating range that you find to be too rich.

If it is excessively loud your packing is likely blown out. Re-pack the silencer.

The GYTR has an optional quiet insert available from FMF.

Re-pack with FMF packing

Stock is so restrictive that it will cause the bike to run very hot.



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