What gives a motorcycle (2 cylinders) that deep rumble?

[CamaroC-17]

So while I'm waiting on my girl to finish getting her hair done I keep hearing these motorcycles going by the shopping center. When they are further down and they rev the engine it sounds comparible to a roaring V8. So what gives? Why is a 2 cylinder V-twin getting such deep amazing sound when even our V6 camaros with after market exhaust doesn't come anywhere close. The V6 even had sorta a ricey sound with stock exhaust. I have always heard that V8s sound the way they do because of displacement. Well a harley sounds awaome and the engine is tiny compared to LS3 or L99. So can someone explain this to me?

[KMPrenger]

Just the way it is....Most V10 or V12 engines don't sound as deep as the V8 does. Hell, my 4 stroke dirtbike sounds pretty damn low for what it is lol.

[SnoopyAce7]

no mufflers/resonators/just short pipes, basically open headers?
dad has a bike, i'm just speculating

[scruffyluv]

I have a HD softail with a vance and hines pipe set and its alot louder than the magnaflow exhaust we put on my 6... but my 6 also grumbles nicely and sounds mean when you get up on the gas!

[Seminole]

Why is a 2 cylinder V-twin getting such deep amazing sound when even our V6 camaros with after market exhaust doesn't come anywhere close. The V6 even had sorta a ricey sound with stock exhaust. I have always heard that V8s sound the way they do because of displacement. Well a harley sounds awaome and the engine is tiny compared to LS3 or L99. So can someone explain this to me?

Displacement per cylinder is what you're looking for.
Think of the thump of a little firecracker compared to a big one. Six little firecrackers may have more total powder, but firing off one at a time they don't make the same thump.

[Eric Baker]

The Harley sound is all in the fact that it has a very large displacement per cylinder, and from the design of the crankshaft, being a common crankpin.

[menendez1293]

plus of the straight pipes and the way they are built. I cant even hear my V6 when i have a motorcycle next to me

[CamaroC-17]

Thanks guys! Now that I think about it, those cylinders on a bike are huge! I was thinking about adding larger pipes to mine to help deepin the sound. Maybe a half inch to .75 larger than stock all the way back. I know now the pipes are larger from the rear axel back. 2.5 inches to 2.75 if I believe. But Im not sure how much bigger it could be without having back pressure problems. I think just cutting of cats or resonators would just make it louder not any deeper.

[scrming]

Originally Posted by Eric Baker

The Harley sound is all in the fact that it has a very large displacement per cylinder, and from the design of the crankshaft, being a common crankpin.

yep....

http://www.howstuffworks.com/question325.htm

[ssmike]

Let's do the math: The Harley 96 cubic inch 2 cylinder V-twin displaces 48 cu in per cyliner. Our LS-3 376 cu in engine displaces 47 cu in per cylinder. This is why Harleys have such a deep exhaust note. The Harley V-twin cylinders are the same size as your average V-8!

[carguy50]

It's all about the size of her 2 big jugs. Sort of ironic, huh?

[Number 3]

It's exhaust, and firing order. Cylinder size as pointed out is not more than the Camaro V6 or V8.

Have you heard the difference between a Harley 45 Degree V Twin and a Ducati 90 Degree V Twin? Both are 1200 cc or so but there is a big difference between the two.

So per revolution you have one cyclinder firing, while on a V6 or V8 you have 3 and 4.

So primarily exhaust and firing order.

Also, at one point HD tried to patent the distinctive sound. Potatoe, potatoe, potatoe.

Oh yeah, I forgot......................LOUD PIPES SAVE LIVES

[camaroitalia]

I was wondering this today... cool

[rydahog]

yes, the LOPING of the cams...give it that...blup. blup, blup sound........
ain't it GREATTTTTTTTTTTTTTTTTTTTT!! )