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Discussion Starter · #1 ·
about time too ..those four bangers much louder than the smokers..not just for the spectators but even on board one



might have a good knock on effect for all off roaders, make us less intrusive in the countryside and under the radar of the usual eco-warrior/concerned parent/residents group/forest rangers etc
 

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've been flagging at an MX national event for the past sevreal years, and the proliferations of four stroke MXers has indeed raised the noise level. The volume trackside is deafening!



Two strokes may put out the same level of noise, but their tone doesn't carry like the four stroke's do.



Off the track, there is no excuse for this level of noise pollution. The AMA needs to come down hard on noise at all non-MX/SX events. I am in favor of drastically reducing sound output at enduros and cross country events.



Noise (and ATVs) is (are) killing trail riding.
 

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102db(A) is actually a rather quiet standard. I would be interested to know what the race bikes are pumping out right now.



The SAEJ1287 method is where the state DOTs will be headed for sound measurement if the state DOTs have not already adopted it. The process is simple- the bike's sound output is measured at 20(?) inches using a calibrated SPL meter. I think the bike is reved up to 50% max RPM in neutral.



The old method (the one that the EPA uses) is significantly more complex. The motorcycle is tested (while moving) from a distance of 50 feet. This requires a suitable test range. PITA!



If you are loud pipes lover then get ready for more spot checks using the SAEJ1287 method. All an officer has to do is:

1. Have someone trustworthy hold his donut.

2. Measure 20" from the outlet pipe of the muffler.

3. Rev up the bike to 50 percent of the redline listed on the tach (accurate? You betcha!).

4. Turn on the SPL meter, take the reading.

5. Get the powdered sugar off the SPL meter.

6. Flip out the ticket book.

7. Exaggerate the motion of clicking the button on the ballpoint pen.

8. Write out the details. Rip the copy of the ticket off the book and hand it to the miscreant.

9. Retrieve the donut. Inspect for unauthorized bites.



 

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So what do you do about bikes such as Aprilias that have no indicated redline, but a user defined shift light? If I set it for 2K, does the cop have to test me at idle?



I like the fact that the AMA is voluntarily taking the lead here, but the last thing we need is a nanny-state hall monitor running around with a meter measuring every other bike he sees. I wish there were a way to legislate common sense so that the idiot on the straight piped bar sled blipping the throttle every ten seconds at 3 AM gets more attention than a guy riding to work with a slightly louder than stock slip on.
 

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What to do about an Aprilia....Impound it, of course!



Frankly there are legitimate issues the police should be concerned with (murder, jaywalking, theft, mattress tag removal, etc.) Unfortunately sound enforcement- via inexpensive SPL meters- will be seen as a revenue source via ticketing.



The sheer number of "straight piped bar sled" blippers ensures the issue is not going to return to the status quo.



Now stop struggling so we can get this chip under your skin...











 

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Discussion Starter · #9 ·
most enduros (all maybe) in europe must run at road legal level....closed course no restrictions..but they are looking to restrict like the ama...



i believe if the rules were changed in the morning to low noise level all the manufacturers would be out with new cans straight away...and engineered with no major power losses
 

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This is all Well and Good, but how is it going to affect the price of Crack in the Southwest Corner of the track parking-lot?
 

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The redline is pre-defined, as all bikes entered must be approved by the AMA.



We're talking about two completely different things here. AMA MX/SX has nothing to do with road-going streetbikes. If you're talking about the Aprilia 450 V-Twins, they're currently not allowed into Japanese controlled AMA competition. :-(
 
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