- Laguna enforces a sound limit for all bikes. There is no guarantee even a stock bike will pass, though almost all do.
- The sound limit is 90db
- A stock exhaust system is required, or an aftermarket pipe with a "quiet insert" (Like one made by a professional specialist such as Jay Murray: firstname.lastname@example.org , 831-659-4729 ).
- Every bike needs a two or three digit number on the front and right side, six inches tall. Duct tape is fine.
- All bikes are measured for sound, every lap. If your bike exceeds 90dB it will be flagged off the course. If the bike's exhaust pipe is stock you will be given two chances to quiet the bike. Three (3) strikes and the bike is banned for the duration of the event. Sound violations accumulate over the course of multiple day events. If the bike has an approved insert you will be given two (2) strikes before the bike is banned, and a bike with an aftermarket pipe with no insert will be banned after a single violation.
- If you violate Carters' exhaust pipe rule -- your bike has an aftermarket exhaust but no quiet baffle, e.g. -- a single noise violation will end the day for that bike.
- Unfortunately, we are unable to tell you in advance whether your bike will pass. Many factors come into play including wind speed and direction, air density, cloud cover, engine and bike speed, distance from the sound booth, etc. Very fast riders, winding out high revving engines near redline, are most at risk.
Sonoma Raceway and Thunderhill
- Limited to 103dB
- Sonoma will randomly spot check with certified sound level measuring equipment. One warning will be given to the rider of any bike that measures 103db or higher. If you exceed the sound limit a second time, your bike will be done for the day.