FMF factory 4 spark arrestor?

My son just picked up a 04 yz450. It has a factory 4 system on it including the power bomb header. The guy he got it from rides mostly desert so he wasn’t concerned with noise or a spark arrestor but personally I feel the bike it too loud. My son wants to go ridding with me and I ride where both spark arrestor and sound db are enforced. Is there something I can do to the exhaust to quiet it down a bit and make it USFS approved?

FMF makes a spark arrestor for it, but I don't recall a "quiet insert".

I'm not sure how loud you can be, but...

I have the powerbomb header and Titanium 4 muffler (titanium version of the factory 4). The BRC sound tested me last weekend and I was at 98.5 dB with the quiet core and fresh packing.

On another note, my wifes 250F checked in at 92 dB. Its equipted with a FMF Q2 muffler.

Thanks for the info! I was looking at the FMF website but no pictures are available for the insert or spark arrestor so I wasn’t sure they were the right style….maybe I’ll give FMF a call just to make sure. I think I’ll start with the spark arrestor and fresh packing before spending the $$ in the insert and see how it sounds.

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