We can police ourselves or do nothing … and eventually let the governments make our decisions for us. (Don’t kid yourself, townships coast to coast are closing down race tracks and passing noise ordinances, some making any form of off-road recreation illegal. Go ahead ignore the issue and your town will be next! And guess what governments have big taxpayer budgets funded by YOU and everyone else. Who do you think can afford the better lawyer and more of his time?)

Read on.



By Bill Dart, AMA District 36 Legislative Officer

Noise has always been one of the biggest reasons people don't like dirt bikes. I am not talking about just environmental groups that don't like OHV recreation on general principles and philosophy, either. We can deal with almost every issue they raise. We can deal with water quality, air quality, erosion, wildlife issue, botanical issues, archaeological issues, and user conflict issues. Often, all of these are just surrogate issues for the real, underlying reason; nobody likes noisy dirt bikes.

I don't think we will ever be able to satisfy environmental extremists, but we need to quit making the general public mad at us over noise. Susie Soccer Mom doesn't like noisy dirt bikes. Joe Six Pack doesn't like noisy dirt bikes. Virtually every single elected official, appointed regulator or public land manager, doesn't like noisy dirt bikes. I don't like noisy dirt bikes.

Noise has always been a major issue, but until a couple of years ago, the trend was towards much more quiet dirt bikes. Water cooling, tighter engine tolerances, better induction systems, and better mufflers had brought the sound level of most dirt bikes down into the mid to low 90 db range by the early 90's. Most of the older, louder air cooled bikes have gone to that big riding area in the sky, or are rusting out behind the shed under a tarp, and noise complaints had dropped off as a major issue.

So what happened? New four-strokes are what happened, especially the popular Yamaha 400/426 series. While right on the margin of legality, they are still too noisy right out of the crate. But the problem really gets bad when an aftermarket exhaust system is installed, which it seems about 90% of these bikes have today. Dirt Rider magazine did testing for power and sound levels on all of the popular exhaust system available for the Yamaha 400/426 series, as well as the new Suzuki DRZ400. According to their testing, the Yamaha measured 100 db stock, barely within the 99db, plus or minus 2 db, mandated by California law. But none of the aftermarket pipes tested came in below 102db, and most were between 104 and 106 db. This means that NONE of the aftermarket pipes for the 400/426 are legal to use anywhere on public lands in California, not even for racing.

"But, those are racing systems," is the response from the aftermarket companies. Baloney! AMA rules have a maximum noise level of 99db. None of them are legal for AMA amateur racing. And what about other private tracks that aren't AMA? Well, many of those tracks have been shut down. Why? Because people hate noisy dirt bikes! I asked most of these companies if they had ever tried to get a permit for a new track, as I have several times. I bet you can guess the single biggest reason why many tracks are never granted permits. If you guessed noise, you are starting to get the drift on the noise issue. Even the thin thread of credibility about the YZ400/426 being a race bike and the aftermarket pipes were designed for closed course racing, went out the window when we read a similar test on all of the pipes for the Suzuki DRZ400.

Unlike the Yamaha, the Suzuki doesn't pretend to be a race bike. It is a recreational trail bike that would cost more to make truly race worthy than a couple of Yamahas. It makes very good useable power, but less than the Yamaha. What really impressed everybody who has heard one is just how quiet it is, yet it still has outstanding performance. Dirt Rider tested it at 90 db with the stock pipe, which is very quiet, and it still puts out over 40 horsepower. For comparison, the latest 426 Yamaha has about 45 horsepower and the Honda XR 400 puts out just a little over 30 horsepower.

Well, the DRZ400 noise got just about as bad as the Yamaha, once the stock pipe was replaced. Not a single one is AMA legal, according to the Dirt Rider data. Only one is barely California legal, the Stroker spark arrestor model, at 100 db. All the rest are between 102 and 104.

But, what about all that extra power that comes with the noise, isn't that reason enough? Well, in the case of the Yamaha, none of the pipes even matched the stock pipe's midrange, where most riding is done. Most of them made less than one horsepower more than the stock pipe. A couple made less than two horsepower over stock, one at extremely low RPM, and one at nearly 11,000 RPM. In fact, some of them were even lower in power than stock at almost every RPM. A one horsepower gain at the ends of the powerband, while losing several horsepower in the most used midrange, does not amount to a performance increase.

What about that choked down Suzuki? It must have made major horsepower leaps with an aftermarket system, right? Sorry, Charlie! Only modest gains were made, a horsepower or two. Barely noticeable. But, boy, EVERYBODY noticed the difference in sound levels.

Expect Heavy Noise Law Enforcement in 2002

Where do we go from here? Well, the OHV Division just convened a committee to address the noise issue, of which I am a member. They have been charged with developing a recommendation for a new sound limit law. The Motorcycle Industry Council has already recommended that level be lowered to 96db, with no plus or minus variation, as a level the industry can comply with. This is likely to be the highest the new law will allow.

"But so what?", you might say. Nobody is enforcing sound limits anyway. Well, things are changing in this field as well. Noise enforcement will be a priority next year. The OHV Division will be providing all of the test equipment needed to every agency that requests it, and the MIC has updated their technical test data manual, so that all models can be properly and legally tested. Additionally, with law enforcement grants exploding this year, and the new state emphasis on noise enforcement, you can expect rigorous field enforcement this year all over the state.

Due to the new emphasis on law enforcement, and the enhanced communication between all of the various law enforcement agencies dealing with OHV's, the sound level of the aftermarket four-stroke exhaust systems has been recently circulated throughout that community, and anyone with an aftermarket exhaust on a four-stroke will be automatically suspect, and the officer will have probable cause to do a stop and sound test.

If you have been considering buying an aftermarket exhaust for your four-stroke, you might want to reconsider, especially if you can't get reliable data that it meets current laws. If you'll want to use it for the long term, you'll want to look for pipes at or below 96 db, since it is almost a certainty that the noise limit will be lowered. The only debate will be about just how much it will be lowered. If you already have an aftermarket system that is over the legal or AMA limit, I would urge you to demand a refund, since it is not even legal for AMA-sanctioned, amateur closed-course racing.

More important than being technically legal, if we really love to ride and want to protect our sport, we need to do everything we can to reduce noise well below the legal limits. We need to make friends, not enemies, and all we really get from noise are more enemies -- except for a few companies making significant money selling socially irresponsible products for big bucks. Can anybody give me a believable reason why a four-stroke exhaust system, with a simple head pipe and a simple can muffler, costs twice as much or more, than a two-stroke system?

Let's bring back the programs that brought the noise levels down before. TEAM STEALTH. Less Sound = More Ground. We need to reward companies that make quiet yet more powerful and lighter pipes. We need to make quiet COOL, instead of nerdy, like the undertone in the enthusiast press does today. We need to harass our fellow riders using obnoxious pipes, until they do something about it. Because, if we don't, all we are doing is digging our own grave.

I have been considering, and trying to find info on the FMF Power Core Q. Anyone have any experience with this pipe? FMF's website claims that their testing produced a 93 decibal level for the YZ 426, while keeping stock power.

I have one on my 2000 yz426 with the stock header.

It really is quieter than the stock muffler. As for the power I can't really give you an honest comparison. I put it on soon after I bought the bike. I only rode with the stock tailpipe a few times. I will offer my opinion though. With the "Q" the bike still seems as quick and powerfull as it did those first few times. There isn't a trail, hill or track that I feel a handicap on as far as power goes. Of course I'm not Tim Ferry, but I think if what you're looking for is a much quieter system without a noticeable loss of power then the "Q" is the way to go. At least until all the other manufacturers realize that this is a legitimate need to the future of our sport/pastime!

I would buy a 426 in a heartbeat but then i would have to find new riding partners. Until everyone grows up and realizes loud doesnt equal fast and quiet doesnt mean restrictive and slow, its not going to change. Loud pipes are like crack, some people take a hit and just cant put the pipe down. I refuse to buy any of that aftermarket garbage. Dirt Bike Magazine is a total sell out. Pay them enough $$$ and they will say your product is the next coming of Christ. One example would be this product test on page 42 of the feb issue. They tossed on not one but three during a break and then jumped up and down about all the massive gains, easy installation ect. I have talked to 6 buyers of this unit so far and ALL were shocked they paid $300+ dollars and then had to cut this, bend that, remove this part, custom make another part, weld this, fabricate that ect..ect...ect...just to get the thing to even fit right. To make matters worse, not one said they noticed any power increase and all said the bike was louder. Hmmmmmmm...i guess another marketing scam, fueled by advertising dollars in my opinion. Then again, maybe the gain is an amazing 1/2 horsepower and worth the $300+ dollars and headache. I think our sport would be much better off if we all had quiet stock pipes and took half the money we would have wasted and used it towards saving our riding area's so our children can enjoy off roading when they reach our age.

I have a loud azz pipe, a FMF Power Core IV squared on a '99 YZ400. I wish it was much quieter than it is, but I do not have the stock pipe, so I am screwed. I bought the bike used.

I'll admit, the bike sounds fast, but going fast is up to the rider. A stock YZ400/426 is a damn fast ride, so an aftermarket pipe on these bikes doesn't do a whole lot. A header and pipe may move/mellow the "hit" around a little, but at the cost of noise. My riding buddy rides a 2000 CR250 and it positively whispers next to my YZ. Nobody can deny a big 4-stroke sounds awesome compared to a 2-smoke.

But, honestly, I'll take a quiet bike over closed riding areas any day of the week.

Continuing on this subject, another contender I see in the quiet pipe arena is the Big Gun quiet series. The promise 94db or lower, which is very quiet as dirt bikes go. Has anyone used this unit and if so what are the results?

Hey dirtdad, thanks for the reply. That's exactly the kind of information I was looking for. I am not trying to make the bike faster, just quieter, without a noticeable loss of power.

Did you have any problems installing the muffler?

I wouldn't really call it a problem, but the slip fit over the header has no gasket like the stock system. It did leak a little so I just used hi-temp gasket seal and that worked fine. Now I do remember some members complaining that the can was too long and prone to damage in a fall, but I haven't had any problem in that respect either.

Bottom line is that in my opinion (seat of the pants testing) the bike is MUCH quieter than stock and still performs as advertised!

[ February 14, 2002: Message edited by: dirtdad ]

[ February 14, 2002: Message edited by: dirtdad ]

THUMPSALAD, i've got a stock pipe (complete) i'll sell ya if you want it. jimbo

Dana Davis,

Excellent reply and you killed me with the comparison with crack, ROFLMAO! I totally agree, man.


I am wondering what product you are talking about in your quote.

They tossed on not one but three during a break and then jumped up and down about all the massive gains, easy installation ect. I have talked to 6 buyers of this unit so far and ALL were shocked they paid $300+ dollars and then had to cut this, bend that, remove this part, custom make another part, weld this, fabricate that ect..ect...ect...just to get the thing to even fit right. To make matters worse, not one said they noticed any power increase and all said the bike was louder. Hmmmmmmm...i guess another marketing scam, fueled by advertising dollars in my opinion. Then again, maybe the gain is an amazing 1/2 horsepower and worth the $300+ dollars and headache.

I have a W/B e-series and had to cut nor bend or twist or weld or fabricate ANYTHING.

I also have a Noleen and had to do no bending/twisting/welding/fabricating anything.

I think most aftermarket things actually fit better than the stock Yamaha stuff! :D

Let us know what product you are talking about.

I am not about to claim I am FOR loud pipes but I AM for the freedom of choice. I also believe that restriction of exhaust flow is restriction of power after a certain point. Afterall.......if you put a Toyota Camry exhaust on a Corvette , how much HP loss do you think you would have? NONE? I would wager my next paycheck to say at LEAST 40% loss.

I don't need the loudest bike on the planet. I am not saying that .......BUT if I wanted an XR trail bike I would BUY one!!!! :D

I also understand the policing ourselves theory too. I am not saying we need louder bikes only freedom of choice.

Once again if I wanted a trail bike I would have bought the XR or DRZ! But that is not what I wanted nor ever will.



just because we like our aftermarket pipes that may actually be quieter, who knows, than the stock Yammy , does not mean we are drug adicts or have any association with CRACK pipes. I really take offence to these allegations. :)


What kind of bike do you ride?

Where do you ride......or rather what kind of riding do you do?

What kind of pipe do you have on it?

Do you have any of that "aftermarket garbage" on it? Such as

Hand gaurds?

Diff brand of tires?

Diff brand of chain?

Air filter diff?

Disc gaurds?

New Plastics?

New levers?

Gas tank?


Seat cover?

or is "everything" on your bike stock?


[ February 14, 2002: Message edited by: THUMPIN' ROCK HUCKER ]

Did anybody here ever hear of an ANR (active noise reduction -I think)exhaust system? I saw a tv program that did a story on a company that is developing this type of system for automobiles. I know there are ANR headsets in use in avaition. These headsets are incredidbly quiet when you switch the noise reduction on. I dont know much about this technology, but I think basic idea is that a sound generator creates the same frequency noise (just out of phase) from the source (muffler) and the system amplifies the out of phase signal and wala...greatly reduced noise (or something close to that). It would be great if someone came along with a lightweight unit for mx bikes. We would be able to reap the H.P. benefits of a less restrictive pipe and not have to worry about the noise.


I run a DMC header and exhaust pipe. It is the loudest pipe on the track. It sounds really good, but sometimes I wish I had a more quiet pipe so my neighbors dont have to endure the sound so much. They're nothing like me.

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