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Sound Check Procedure.

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Sound Check Procedures.

The Pacific Northwest Motorcycle Association is planning to enforce a 96dB sound limit at all it's off-road events. Also there is a mandatory requirement for spark arresters as well. Right now, it looks like we're going to follow the AMA guidelines for sound. My main concern as part of the PN Exec is to make sure that the sound check proceedures are efficient and effective. There was concerns that riders will uncork their bikes between the sound check and start. This means that an impound system will have to be used or checks will have to be done at the finish. Bikes failing the check will be disqalified. Please do keep in mind that things are at the roughing in stage here. I'll try to convince the rest of the exec to make the penalties for failure less severe for the first year so that we all get a chance to get used to the proceedure. Do any of you have any opinions or suggestions for sound checks, I would love to hear it.

Mike Fodor - PNWMA Secretary.

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One thing to consider is to make sure that bikes are tested at the proper rpm. My Husqvarna TE 570 ain't yzf and it should be tested at a much lower rpm. I think a penalty should be strong becuase there are people who change silencers after thay make sound. An after race test would be cool, like they do in World enduro.

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Exactly why is sound an issue? Iv never found an answer other than "it can damage hearing" and "it annoys the neighbors" Neither have really satisfied me.

And is this enforced only in events? Would they check my bike at an ohv park? Iv been riding for awhile in various spots in Oregon and have never been checked for anything but my tags. Im sure I would break the sound limit because you can hear my big 2 smoker over most of the bikes around and I have been around many "officials" that dont seem to care much. Iv also gone offroading in a friends truck with a chevy 350 running straight headers and nothing else. Louder than [@#$%&*!]! the guys that should be stopping us were standing right by us talking to us as we unloaded and never said a word.

Eh...

Later,

Dan

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I'm the sound check guy for a dual-sport club I belong to that has a 92 dBA noise limit for any of its organized rides. We follow AMA Guidelines when doing the sound checks- sound level meter (SLM) at a 45° angle and 20" from the exhaust tip, engine at 3400 rpm, A-weighting, slow response. 3400 rpm is recommended in the AMA guidelines as a good all-around engine speed for sound testing purposes. We use a sirometer or tach readings to determine engine speed. A sirometer can pick up the engine's crankshaft frequency through vibration and is pretty accurate and cheap. I got mine from a lawn mower shop and it is made by Tecumseh.

I know these types of measurements can seem very subjective and are easily affected by local conditions, so here are a few things to look out for if you get stopped for a sound check. First, make sure you aren't real close (10 ft.) to any large vertical surfaces such as trees or buildings which can cause the reading to be higher because of echoing. The SLM should be calibrated at least daily and they should have a calibrator readily available. I calibrate my meter once a day when doing these tests and it often needs adjustment. The meter should be set for slow response and A-weighting. If either one of these settings are different, e.g, fast response, flat-weighting or c-weighting, the readings are invalid. These are important because they can easily cause a passing bike to fail. When I'm doing the testing and a bike fails, I first check the weighting and response settings (all decent SLMs should be switchable between different weightings and response speeds) to make sure I didn't accidentally move the switches as I was holding the meter.

One way to make the testing go smoothly is use several people. One to hold the SLM/take the readings, one to hold the sirometer, one to operate the throttle, one to control the flow into the test area, one to record the results and one to mark the bike as passed. We use tape to mark the inspection area and we don't allow one bike to enter the chute (about 50' long) until the bike we are testing has been checked. This way, they don't get the sound adding together making the reading too high. We also setup a system whereby registrants have to have proof of passing "tech inspection" before they are even allowed to pick up their registration packet. The proof is provided by us giving them a preprinted tech inspection form with the results on it and a sticker on the form to authenticate it.

As far as impounding the bikes and/or doing a post check, that's up to you, obviously. It is our experience that very few people modify their bikes after the tech inspection, although I know that some have. It could make it unattractive to participants if their bikes are impounded and they are unable to do any last minute tweaking and this may reduce attendance. Post checking seems the best option but it is time consuming.

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Another thing is that you can use the first events you have as a way to educate the attendees about the noise level their bike puts out. If the bikes are too loud, let them know that a good quality repack job or removing a few discs from the muffler makes a big difference in the sound level. Send them back to make the changes and then let them come back through. If they made a significant effect on the noise output (3 dBA or greater) let them pass this time, even if they are a little above the 96 dBA limit.

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Thanks Rich for the advice.

And for everyone, the reason why the PNWMA is starting to enforce the sound limit it to preserve the sport. The Fraser Valley had 10 riding areas open with a few close to civilized areas. Now we're down to five. It would be stupid to do nothing. The sound enforcement will reduce the impact of the sport on other user groups. I know idiots run around with open pipes and loud exhausts, but it is easier for groups to target clubs and associations. Enough idiots with loud pipes run around and suddenly we stop getting permits that allow us to run events. Without events many clubs will stop maintaining trails since the events pay for trail maintenance. With a sound and spark arrester we can at least say that we're trying.

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Less sound = more ground. There really are no benefits to excessive noise. I take the steve whitlock stance on this, its a rule, enforce it. Even if noise poses no serious threat, enviros will use it to nail our coffin.

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Thanks for the input guys. One of the issues that we had come up was that not all bikes had spark arresters. The original mandate of the PN off-road series was to provide a cheap source of racing, so we're not sure if we want to impose that kind of financial hardship on the riders. Then again I hate riding through a scorched riding area.

Also I think for the first year of the program I would like to educate riders on how to quieten their bikes. Do any of you tech savvy guys have any tips and suggestions that I can pass onto the unenlightened masses?

Thanks a bunch.

Mike <--- pilots a quiet DRZ400E. :cry:

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if it's possible, find out how other clubs atre sound checking and copy it. i find the results of sound checks at local events here in western WA vary widely. at one event i was waved through without a check (they do this with bikes they can barey hear at an idle). at an enduro 1 month later i barely squeaked by the sound check with a 98db. i know it didn't all of a sudden get super loud in one month.

jeremiah

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i know over here in district 36 they do drive by sound tests during our races, to check if we have changed our silencers since the sound test, and also at some OHV parks they do check i got popped with a $100 ticket for being to loud at hollister :cry: :cry:

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Thanks for the input guys. One of the issues that we had come up was that not all bikes had spark arresters. The original mandate of the PN off-road series was to provide a cheap source of racing, so we're not sure if we want to impose that kind of financial hardship on the riders.

I don't know if it's still legal, but we used to use steel screen and a hose clamp to make a spark arrestor when it was a requirement for a dez race, in Nat'l Forests....pretty cheap and functional, not very pretty, though. :cry:

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Exactly why is sound an issue? Iv never found an answer other than "it can damage hearing" and "it annoys the neighbors" Neither have really satisfied me.

Those are two pretty good reasons.

All of the informal riding areas I used growing up are closed and everyone was closed initially due to noise complaints.

There are more and more people. Everyone has their own idea of what the Forest and other land areas should be used for. Keeping the sound level around 96 db is about using your fair share and not noise polluting the area for miles around. I don't know about you, but I don't like loud cars and loud motorcycles when they drive by my house. There is no need for it. The same applies to the open space areas.

The side effect of keeping the db limit of 96 at races is most of the motorcycles get set up for that standard and are ridden elsewere using that standard. Slowly motorcycles become a bit quieter.

I had a loud dirt bike when I was 17, but that was 30 years ago and times have changed. The population has atleast doubled.

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