I will be testing the limits of the law this winter in Wi. I'll let you all know how it goes. Last year they were extremly strict on exhaust. My buddy was stopped and questoned for a long time because of his STOCK Indy Storm. While waiting, there was a number of sleds that were being loaded on trailers because they had aftermarket exhaust - not loud exhaust, but aftermarket exhaust. Wi DNR says now that you can have aftermarket exhaust, but it must be as quiet, or quieter that stock. And that determination is left up to the conservation officer. There are two laws that can be enforced. One states that a sled bought or sold in Wi after 1975 has to have a dB output of no louder than 78 dB. The other part states that no person can modify an exhaust as to increase the sound level above the level that it was when it was originally manufactured, regardless of the date of manufacure.
If I interpreret this correctly, your sled must be at or below 78dB (at 50 feet) to sell or buy in the state. If you modify the sled, and you increase the noise emissions above what it was at when it was originally manufactured, you are also in violation, even if you were below the 78dB.
So, I have my trusty dB meter, and I am testing ways to lower my sound emissions to be below 78dB. Once I am in compliance - I will be testing the law.
Now don't get me wrong. I feel that we all need to help lower the ear piercing screams from the sleds riding by the cabin at 2am. But, I also don't think that it is right to ruin someones snowmobile trip because of interpation of the law. If sleds have to be below 78dB, then so be it. If you can not replace the original exhaust on your sled, then so be it. We as avid snowmobilers just need to know.