If you find a USFS spark arrestor that works, please post the results. I've been hassled a few times now by the park rangers in the OHV area parking lots. They always "let me off with a warning this time, but next time..."
I'm planning to upgrade the entire exhaust at some point this summer, it's the only mod left. I was thinking I could try to fit one of these in a cheap muffler:
https://www.ebay.com/sch/i.html?_fro...estor&_sacat=0