Snowmobile Muffler Requirements As of July 1st, 2026July isn't when you usually think about snowmobiling, but that's one of the big laws that has changed on July 1st. The DNR is cracking down on excessive noise from snowmobile exhaust. They are specifically targeting aftermarket exhaust that produces a sharp popping or crackling sound. An aftermarket muffler will be required to have a stamped certification requirement. Stamp Requirement For After-Market MufflersBeginning July 1, 2026, all after-market mufflers installed on a snowmobile must have a permanent stamp, clearly visible on the muffler, certified by the muffler manufacturer and stating that the muffler conforms to the snowmobile muffler noise limits specified by the rules of the commissioner.