Does anyone know if there is a "standard" way to measure sound levels? Do they measure at 2000 RPM, or just take a peak sound level at wide open throttle? And if they measure sound level at a predetermined RPM, how do they know they are at the correct RPM on an ATV without a tachometer? And do they measure sound levels standing beside the ATV, or behind the ATV?

If they measure behind the ATV, at wide open throttle, then my DS would flunk the test big time. I used a Radio Shack sound meter, and an HMF slip-on with no spark arrester has a peak sound level of 130 dB at wide open throttle.

I have had a Ron Woods pipe on a previous DS, and it was not nearly this loud, but I did not care for the fit of the Ron Woods pipe. I would say that the HMF slip-on makes more power and torque down low in the powerband, and is equal throughout the mid-range. The Ron Woods pipe makes more top end power though.

OuterLimit.

 

From what I understand they use a sound gun 20 inches from the exhuast they have a moduale that measures the rpms, I am not shure at what rpms the bike is tested I thought 4000 but I am nto sure on that. Here in California the level can't exceed 96 db[img]i/expressions/face-icon-small-frown.gif[/img]

 

Most sound check call for a reading at 1/2 max RPM listed by factory. For a DS that would be around 3250 to 3350 RPM depending on model and year. Take 20 inches from the end of the tail pipe at a 45 degree angle.

 

They tested mine at my last race with two meters. One rested on the fender above the end of the exhaust. It read the rpm's. The other was a metal flimsy rod that was a little longer than a foot attached at the end was a little guage thing. They stuck the end of that rod right at the tip of my exhaust.
They all thought the tach I had was really cool.
They had a chart with the different models and different pipes and what the readings should be.