Neb. Rev. Stat. § 60-6,339: Snowmobile; operation; muffler, when required.

Except as provided in this section, every snowmobile shall be equipped at all times with a muffler in good working order which blends the exhaust noise into the overall snowmobile noise and is in constant operation to prevent excessive or unusual noise. The exhaust system shall not emit or produce a sharp popping or crackling sound.

This section shall not apply to organized races or similar competitive events held on (1) private lands, with the permission of the owner, lessee, or custodian of the land, or (2) public lands, with the consent of the public agency owning the land.