Maybe I missed it here; I don't check your website very often as I live outside of a high speed connection area, but I'm a little curious about your magazine's statements about the KTM 250 SXF and the sound issue. In your 250 four-stroke shootout (February 2006) you made mention of the Japanese four-strokes having an ignition curve that retards timing/reduces noise. While it's just a small note in your "by the numbers" column, it did cause me to question that if you're really serious about reducing noise, you might want to consider how effective a stationary sound test will really be if the manufactures are going to modify the ignition curve with the intent of passing sound tests. It implies to me that as manufactures and the aftermarket get more technical, they can and may be able to pass sound tests while producing a product that is louder in actual use than what it was before. Anyhow, it does warrant some consideration as to future sound requirements and testing.
I'm just a play rider, but having observed Michigan go from virtually open riding to their current restrictions, I've felt the noise issue is a great concern. Several of these trails pass fairly close to homes. I believe that if you're not seen and not heard, most non-riders are not going to be concerned with riding, and consequently, be indifferent to off-road trails. However, if they have to listen to loud motorcycles all day, it's a different situation thats more likely to elicit opposition to [open] trails and riding. I believe it's the same situation with both automobile and motorcycle race tracks.
Anyhow, I am appreciative to see your positive support on reducing noise and hopefully it will help keep riding opportunities open.
We are serious about the noise issue and are doing our best to be fair, honest and informative without outright killing our sport in the process. Let me explain:
At the current sound limit, which is 99db for AMA Amateur motocross, it is very easy to make a muffler that passes that sound limit at the prescribed stationary RPM in the Motorcycle Industry Council (MIC) handbook. At 99db you can have a really loud muffler and pass with some fancy ignition work, true. But it is still better than a muffler that blows a 102 at the same RPM, in other words 99 is better than 102. We are in the process of taking steps forward, at a speed that the industry and the sport can live with. That is why Dirt Rider took the step from the 102db limit last year for our aftermarket pipe comparison down to 99 this year (January 2006). We will currently use, and will continue to use, 96db as our off-road noise limit.
The stationary sound test, SAE J1287, is the only affordable, enforceable and repeatable way to test sound right now. Those three things are key in an equation that makes it possible to police and enforce the sound issue. And even with a stationary sound test, at an rpm that is acceptable for an accurate test (half of peak horsepower is basically the RPM that is used for the stationary test), the bikes will be getting quieter as the limit comes down. Even AMA Pro Racing is looking at bringing down the level to 99db next year. Small steps will make a big differenceanyone who was at the first sound-regulated Supercross race can tell you that. You can only "cheat" the test so much, then you have to actually make the bike quieter.
And trust me, we are getting flack from a lot of the pipe companies (advertisers) who aren't really happy with us. They tell us that quiet stuff isn't what they are selling so it shouldn't be what we are testing. But we feel we are a step ahead because they won't be selling many loud pipes if there isn't anyplace to ride them. The minute your track closes because a group of concerned citizens complained about noise will be a minute too long riders had their heads in the sand. It may not happen tomorrow, but it is coming, unless you do something about it now.
The interesting thing is, and you will start to see this as the sound limits go down, that mufflers will have to get better. As I said, it is easy to pass 99. Getting to 96 is harder and it takes a toll, mostly on throttle response, or the "snap" feeling a bike gives. But being quiet does not hurt the power output if it is done correctly. That is a myth perpetrated by people who know that the easy way to more power is to make a loud pipe. Currently in the World MX Championships (Europe), the sound limit is at 96db and they test at a higher RPM than we do in the US, so there are some pretty interesting mufflers (and pre-mufflers) popping up on the scene. This technology will likely be seeing its way into production and making it's way over here soon, as the repercussion of the sound issue is just getting started.
I appreciate your concern and you are on the right track with your position on motorcycle noise. Do the right thing and spread this to others who may not be so informed. Because we are trying to do it on our end, but in order for our sport to keep on growing, we need to have places to ride. And riding around on obnoxiously loud bikes will not help us at all.