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Quiet Exhaust Part 2

31 posts in this topic

What exhaust has been proven to be under 96db's on a WR? I have had a WB promeg with 4 disc's and a quiet insert that failed at 99. A FMF Q that failed at 98. Now back to a stock 426 silencer with a PB insert, quiet but have not tested. Thinking about a PC 496 or waiting for the E2. Any idea's :)

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Before calling it quits with your FMF Q, you might try repacking it.

I know that some of the guys I have ridden with were passing on WR400's at 96DB on those. Seen it.

It's a lot cheaper than selling it at a loss and buying something else that might not work.

I bought a new CRD that was suppose to get under 96DB and it failed big time. I was pissed because Ligne Racing went out of business so I could not send it back. I repacked mine and went back out. Well, I failed again, but a 2 DB difference. Keep in mind that the first time I ever tested it was brand new, but I guess they did not do such a good job of packing it from the factory.

Also, having the powerbomb header vs stock is suppose to help... anyone confirm?

In any event, the rangers have an allowable margin of error, so even if you are slightly over 96DB you should be able to ride for fun (that may be different if you were competing?).

One thing that I have observed is that when your pipe/bike is warmed up it will be louder than when it's cold (by 1 or 2 DB). So if you are going to test make sure that you don't ride around like a mad man while your buddies are getting tested before pulling up to the ranger :)

Of course if you are just looking for an excuse to buy that E2... let me know how it works out! You might convince me since I still have to test with a new mod I made to my CRD :D

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I bought an FMF Q from someone on TT and it was basically brand new/perfect. I have not had it tested but it is considerably louder than the PMB or GYRT inserts. I still have the PMB and previously had the GYRT.

I seriously question whether or not it will pass 96 db. I'm guessing not but it is quite a bit quieter than the stock open pipe.

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The Q was brand new, on only for 15 minutes before testing. I do want a aftermarket exhaust , but don't want to keep failing the test and annoying other riders. I have heard that the 496 will pass, but right at 96. I suspect it would fail on my bike. :)

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I bought an FMF Q from someone on TT and it was basically brand new/perfect. I have not had it tested but it is considerably louder than the PMB or GYRT inserts. I still have the PMB and previously had the GYRT.

I seriously question whether or not it will pass 96 db. I'm guessing not but it is quite a bit quieter than the stock open pipe.

I'm sorry, but I think you bought it from me :)

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My FMF Q tested at 94.5db when it was new on my WR450. Heard that the testing rangers out here in Calif. will give you 1.5db above 96 before the hassling starts. The sound test has to be set up and executed properly too. Its been a while, so I forget the measure distance to the end of the exhaust and RPM level, etc..

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YZ timing and jetting has increased my noise above stock. It runs better with every modification, but gets louder :)

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Its been awhile since I posted this so......

FMF Q pipe, Silent sport packing - make it LOOSE. FMF power bomb header. Make sure you bike is warmed up! No choke. Know your test RPM. Watch your background....hills...pavement....even trees. Test away! My 426 is pretty quiet...around 94. My 250f is another story...High test RPM.

Tom

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I just had my 2KWR tested at Hollister 2 weeks ago, passed with a 95.9. I had it tested at Metcalf in November, before the powerbomb and about 7 ride hrs later, and it passed in the 94s. Repack it and it should pass.

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I just wanted to add to the above post.Keep in mind if your jetting is off in the middle ie.-fat on the clip,it can impact sound testing as much as 2 db. or more.I noticed a pronounced "poof" sound at 4,000 rpm & above when sound testing for my end cap design.I dropped the needle 1 clip & things seemed to smooth right out-lower 2 db by jetting correction.Just a thought.Jetting WILL affect sound levels. :)

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No worries bud, I wanted the pipe and you were up front with me that it didn't pass your local test. It's a whole lot quieter than my open exhaust , weighs less, makes good power, etc. I don't have quite as tight a restriction on me as you do in CA so I'm not worried. I'm not complaining just commenting on the others posts.

To you. :D:)

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I just had my 2KWR tested at Hollister 2 weeks ago, passed with a 95.9. I had it tested at Metcalf in November, before the powerbomb and about 7 ride hrs later, and it passed in the 94s. Repack it and it should pass.

I sold it, going to try number 4 :)

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No worries bud, I wanted the pipe and you were up front with me that it didn't pass your local test. It's a whole lot quieter than my open exhaust , weighs less, makes good power, etc. I don't have quite as tight a restriction on me as you do in CA so I'm not worried. I'm not complaining just commenting on the others posts.

To you. :D:)

Now that you own it, it really has less than 1 hour on it. 45 minutes of which was sound testing in my garage. I settled on the stock pipe with a insert, and all my friends that said my bike was too loud have bought silencers that are louder yet since. So now I'm looking for a exhaust again :D

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Now that you own it, it really has less than 1 hour on it. 45 minutes of which was sound testing in my garage. I settled on the stock pipe with a insert, and all my friends that said my bike was too loud have bought silencers that are louder yet since. So now I'm looking for a exhaust again :)

If you were using an actual meter to check it, and you were inside the garage, the meter was reading the echoes as well as the actual exhaust noise. You were probably under the limit....gotta do the check out in the open with nothing around to reflect the noise .

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Very true. I was doing some snap throttle tests of my jetting and quick runs up my street. All by ear not metered. Every test done on the bike, by the local state park rangers had failed when the bike's new exhaust sounded quieter than the previous system.

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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. I do not know what engine speed is required for the tests you are concerned about. 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've got a stock exhaust with a GYT-R insert on my '99 WR400. I checked mine this past Saturday and it registered 90 dBA. Previous measurements over the past year ranged from 88 to 90 dBA so it's been pretty consistent.

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. If you are ticketed or told to leave as a result of the noise test, I would request that they make sure the SLM is properly calibrated and then get retested. If they are doing these tests correctly, 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. If they don't have a calibrator then the readings are garbage. Ask to take a look at the meter to see its settings. 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. And sometimes I had moved the switches so it happens to the best of us.

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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.

In CA I am fairly sure they do the checks at 4000 rpm. Therefore a bit louder....

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The checks are performed at roughly 1/2 your engines redline as posted in the Motorcycle Industry Councils website. Hence, 426 lower test rpm than 250.

Your resources are Motorcycle Industry Council and SAE J1287. Test procedure for Sound measurement from the Society of Automotive Engineers.

I have to disagree with the above post concerning the calibration and your right to inspect them at the scene.

If you are up against an individual that is actually going to cite you for noise I wouldn't recommend questioning his/hers abilities and cal. records. That is information that is available for "discovery" at a court of law. Technically the officer/ranger does not have to show you the cal. records at the scene. Just trying to help with some advice.

Tom

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Actually, I'm using the information in Joe Wernex's 2nd Edition Off Highway Motorcycle & ATV Trails: Guidelines for Design, Construction, Maintenance And User Satisfaction for my information but it does reference the SAE procedure and the MIC in it.

I would hope that if it came to it, one would use a little tact with the officer and try to "help" him or her make an accurate appraisal of the sound level. Maybe approach it as trying to educate yourself about the procedure as opposed to a confrontation. If you do it that way might you get a second chance? After all, if you're too loud there's nothing to be done about it and I would hope the officers were trying to be fair and accurate instead of on a witch hunt. Then again, I have encountered law enforcement officers who were just itching to bust me and were pissed that I had all my ducks in a row when confronted. So I guess you just have to evaluate each situation and try to get a feel if it's worth the risk to talk it over with him or her.

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