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Measuring How Loud a Bike is

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Here's a link to how Calif USA parks measure it:

http://ohv.parks.ca.gov/default.asp?page_id=23037

And the coolest link on the subject: actual testing data!

http://ohv.parks.ca.gov/default.asp?page_id=23038

My experience has been this: you walk the bike out into a flat clearing area, probably 60 feet (20m) from any building, car, or other object. You sit on the bike and start it. One ranger puts a small device - a vibration tachometer - on the rear fender and controls the throttle.

The other ranger holds an instrument 20 inches (2/3 meter?) from the outlet of your exhaust. He has a wire rod that helps him maintain the proper distance. I think the micropone is to be held at the same horizontal level as the exhaust outlet, but 45 degrees off to the side.

The proper RPM they look up in a chart... Typically it is around 1/2 of the max RPM of the bike.

And then they thank you for taking the test without having to be asked, and for passing the test (all my bikes pass) and they give you a little sticker to put on your registration

In Calif the limit is 96 dBA at that 20 inches at that RPM. But, MAN, the 4-stroke bikes get WAY louder at higher RPMs and throttle openings. 96 dB is kind of loud in my opinion.

+sean

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The best way is to put Billm on the bike while you listen to it. If it hurts your ears and the ears of all the other riders in your group then it is too loud and should be shelved for those days at the track.

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Bill, I allready did that and it did seem a little loud. However, not so loud that I could not handle it. I guess the only alternative is for me to bring ear plugs for those that are bleeding from their ears.

I am in the process of measuring the sound difference with the Supertrapp insert. I hope it does not lose too much power or cause jetting changes.

You still gotta like the power of the JEMCO!

Jim :cry:

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