Sound testing: Tips and contacts

by Bill Haas, AMA Congress

There are a number of new advances in sound technology being offered. I will touch on a few, but all manufacturers are currently developing new and improved systems so if the information offered below does not address your particular problem, call the manufacturer of your particular system to get individual help.

Pro Circuit tells us that all of their ’07 exhaust systems will meet the 99 dB limit. They also have an insert for earlier systems that will drop those sound output levels to 99 dB. Call Pro Circuit at (888) 727-8537 for technical assistance, or go to www.procircuit.com.

Supertrapp has done a lot of development work on the 450 CRF for both stock chassis and the C&J framer. Kevin Berger tells me that these systems are fully tunable and will meet the 99 dB requirement. Supertrapp is currently finishing up the development work on systems to fit the Yamaha and Suzuki 450s, but these may not be ready before DuQuoin. SuperTrapp has a number of other systems to fit a variety of applications. Supertrapp customer service will be glad to help anyone with a sound problem. They can be reached at (216) 265-8400; this is an automated system so hit the number called out for customer service.

John Easton at Jemco tells us that he has a new “boom box” that will meet the 99 dB limit. John is also working with a new end cap from Purley Custom that will hopefully quiet some of the older Jemcos without a drastic loss in HP. John can offer advice for owners of Jemco pipes at (713) 461-3834.

The Dave Bird pipe Co. has been bought by Joe Cude and are now marketed as Barracuda exhaust systems. Joe has developed some tunable silencing system that are claimed to meet the 99 dB level. These systems are currently available for the 450 Honda with stock frames as well as C & J and J & M chassis. Barracuda is finishing up systems for 450 Suzukis and Yamahas. They also have systems for Rotax and have an end that can be adapted to a Jemco with a little work to the Jemco pipe. Joe is available at (406) 892-7210 after 5 p.m. EST and can help with non-stock chassis problems as well as the “not run of the mill” racer.

dB Dawg claims a significant noise reduction with a very minimal, if any, loss in HP. At this time dB Dawg has a very small dealer network so it might be best to contact Michael Rigdon at (310) 387-1889. Michael is looking for dealers to handle the dB Dawg and other products.

Many two-stroke competitors with loud exhausts have turned to the dB Snorkel. The Snorkel is only available through Sydney Gearing at (800) 694-0287 or www.thedbsnorkel.com.

Leo Vince offers exhaust systems for most European and Japanese stock-framed motorcycles. Leo Vince is a European company which has worked extensively with the FIM, who requires lower sound levels than the AMA. Leo Vince has exhaust systems and inserts that test at 98, 96 or 94dB depending on the year and the particular pipe. They can be contacted at (510) 232-4040.

Testing at DuQuoin in 2006 showed that 87% of the stock pipes were at or under 99 dB. This means that unless you are running a framer, the noise reduction solution is really quite simple.

Don’t neglect the fact that all exhaust systems require maintenance. Maintenance means repacking of your silencer. A good and cheap repacking material is a disposable baby diaper available at your local grocery store. These diapers are non-flammable and I have been told do as good a job, if not better, as the commercially available products. These diapers are so cheap that you could re pack weekly. An exhaust that needs repacking is not only loud, it is losing HP.

For more information, contact Haas directly at billhaas1@cox.net.

© 2007, American Motorcyclist Association