Why are motorcycles so loud?

It seems that most all motorcycles, from big road hogs to small dirt bikes, are obnoxiously loud, whether they sound like Thor gargling gravel or a mosquito on meth. Why? Can’t they make mufflers for motorcycle engines?

Stock mufflers are quiet. There are federally mandated limits. You’re hearing the aftermarket/modified pipes.

Motorcycle enthusiasts believe that loud bikes make them safer; they’re easier to be noticed. A colleague of mine bought a new Harley Davidson last year and the first thing he did was swap the factory mufflers for the rumbling loud ones. He said he couldn’t stand the quiet sound of the factory mufflers.

I’m not sure what the dirt bike situation is, but you’re right they can sound like a chain saw at full throttle.

ETA: Personally, for road bikes, I think there’s a lot of dick waving going on when it comes to loud bikes.

Motorcycles aren’t inherently loud. They come from the dealer with mufflers, and are subject to the same noise regulations as cars.

But an unfortunately large percentage of motorcyclists circumvent the regulations by installing “for off-road use only” exhaust systems. They’re incredibly annoying. Harley riders are the worst offenders, but riders of Japanese motorcycles are nearly as bad. BMW riders seem to be a bit less dickish.

The real question is why the regulations aren’t enforced. I’ve never even heard of a motorcyclist getting a loud pipe ticket around here.

It’s people like that who make me wish Hell was real.

I kept my factory mufflers on, and my bike (Ninja 650) is pretty quiet even at full throttle.

Because they’re driven by attention-seeking inconsiderate assholes. Decent people, like Una, can drive a motorcycle without feeling the need to make everyone aware of the fact that they’re driving a motorcycle.

There’s a bumper sticker that says “Loud pipes save lives” but that’s debatable – the noise is being directed behind you, when the people you want to alert are ahead of you.

So it’s mostly dick-waving.

When lane-splitting (legal, here in California) a modest amount of engine noise is a good throat-clearing “excuse me, but I’d like to pass through and could use an eentsy bit more space, thank you”.

My pipes are factory-issued.

Well it just depends on the rider and the image they’re trying to portray. A lot of HD riders are into the macho rumble or blast of rocket fire they can get from loud pipes. Some of the sport bike riders like em loud too.
IMHO, there is no sweeter sound than my Vespa GTS 250 purring along a country road at 45 mph. My 2-strokes, though… well they are a bit loud. And fun.

They’re toys.

This is what I thought but wasn’t quite sure how to phrase it. Nicely done, Leaffan!

Thank you for being considerate, Una. I wish all riders were. There are quite a few bikers in my neighborhood and I’m with Procrustus, I wish Hell were real so I could wish them all into it!

Saintly Loser has the best question: why aren’t the noise regulations enforced?

Even if it were proven fact that loud pipes save lives, it doesn’t matter. That’s irrelevant.

By that logic, I should be permitted to attach a siren to my car and drive around with it turned on, blowing my horn as I go.

Sooner or later, one of the loud pipe brigade will come in here and assert his “right” to run straight pipes. To him, I say, yes, it’s dick-waving. And my credentials to hold that opinion are I don’t know how many hundreds of thousands of miles on motorcycles (Japanese, American and German) over thirty years.

Not only that, but the emission regulations are violated when stock mufflers are removed (catalytic converters are removed). Not only do these douche nozzles think noise regulations don’t apply to them, but screw the environment too.

Someone really needs to ask the EPA why they turn their head to this problem.

Even apart from the “loud pipes” nonsense, there’s reasons why it’s easier to make a quiet car than a quiet bike. With exhaust noise, the exhaust system is much shorter than a car so it requires a lot more work to get it quiet without creating too much backpressure. Motorcycle engines also typically run at higher (sometimes much higher) RPMs which also makes that a challenge. You also get a certain amount of noise coming from the engine itself, which is usually well-baffled in a car but is outside for everyone to enjoy on a bike. That’s doubly true with an air-cooled engine.

Then why are the stock pipes so much quieter?

It would be more accurate to say: Motorcycle enthusiasts believe that “Loud pipes save lives” is a handy way to rationalize obnoxious behavior.

When I see a motorcycle set up to direct exhaust noise forward, I’ll believe the owner is sincere about the safety value of noise. Ain’t happened yet.

They’re quieter, but your average motorcycle is still a lot louder than your average car in stock form.

With motorcycle exhaust systems, you can pick two out of three: quiet, efficient and cheap. Higher end bikes have very clever but spendy exhaust systems that keep things quiet without compromising performance. With cheaper bikes though, the manufacturer has to make the trade-off between noise reduction and performance. That means that many of those bikes come from the factory close to the DOT noise limits, whereas on others they use restrictive pipes and mufflers to trade performance for decibel reduction.

I won’t claim that every (or even most) loud exhausts put on bikes is to get back performance lost to restrictive factory designs, but it’s certainly more of an issue on a typical bike these days than a typical car. On a car where you’ve already got many feet of exhaust pipe and adding more baffling doesn’t create space issues, quiet unrestricted exhausts are easy. That’s not so much true with a bike.

My bike (Honda Shadow) is quiet as far as motorcycles go. If I could make it as quiet as a car, I would; it has the muffler that came on it.

I wouldn’t use the phrase “dick waving”. But I’m kind and soft spoken. I’d call it “posturing”.