Interesting debate how a Vulcan V-twin is different than a HD V-twin

[jlreeves]

I've always thought my 1600 motor with V&H duals/UB sounded just like the 327 Chevy Camaro motor I used to have. Others have said the same thing. The Harley guys actually call me V8 when I ride with them.

[Loafer]

Originally Posted by glwilson

No.. Re-read all that's there. HD has a patent on their firing-sequence/timing of their engines. (This is not to be confused with their feeble attempt to patent the sound of their engines. This refers to the firing sequence. It is mentioned in the material on Wikipedia.)

Kaw is not the same despite it being a V-Twin. The V-Twin is just about all that is comparable between the two.

There are issues such as HD's 405 degree firing-gap occurring on the stroke cycle causing some of what you are referring to; along with a few other factors -- but the most noticeable is the firing-sequence with their engines is what you are hearing.

Older carbed engines are more often adjusted to a low-idle where you hear the stutter-step of the timing more so than the fuel-injected models. My previous and current FI HDs only slightly provide that sound when at idle. They simple do not idle slow enough for it to be noticeable.

Too bad Mac doesn't respond to this. He would be someone who could tell you what the Kaw V-Twin does in comparison.

[cnc]

Originally Posted by ubernomad

But correct me if I'm wrong isn't the Vulcan V-twin basically the same engine configuration? Single pin crankshaft. "Wasted" spark system. very close to 45 degree V angle (I think the Vulcan engine is something like 46 degrees??). Seems to me the Vulcan engine would have the same plug firing sequence with a slight difference due to the angle "V" being a little more than HD.

Good story but I doubt it is true. They may have looked at the design of one in building the 45 degree twin but certainly not modify one into a 2 cylinder. Radial aircraft engines are based on a odd number of cylinders around in a circle to get an even firing sequence. They could be 3,5,7 cylinders radiating around the circle and single or multiple rows. A 10 cylinder configuration would be 2 rows of five cylinders which would be 72 degrees apart. Also a radial aircraft engine is not a single pin crank, it has a master connecting rod that all the other connecting rods are attached to.

[hayes]

Originally Posted by cnc

Good story but I doubt it is true. They may have looked at the design of one in building the 45 degree twin but certainly not modify one into a 2 cylinder. Radial aircraft engines are based on a odd number of cylinders around in a circle to get an even firing sequence. They could be 3,5,7 cylinders radiating around the circle and single or multiple rows. A 10 cylinder configuration would be 2 rows of five cylinders which would be 72 degrees apart. Also a radial aircraft engine is not a single pin crank, it has a master connecting rod that all the other connecting rods are attached to.

Good to know. I wish I could remember where I heard that. Oh well. No skin off my back. And people believe it, even the Harley riders. 😉

[blowndodge]

Originally Posted by glwilson

This is directly from Wikipedia; and is as an accurate description of why the sound is produced as one can explain. It is all here...
The classic Harley-Davidson engines are V-twin engines, each with a 45° angle between the cylinders. The crankshaft has a single pin, and both pistons are connected to this pin through their connecting rods.[9]

This 45° angle is covered under several United States patents and is an engineering tradeoff that allows a large, high-torque engine in a relatively small space. It causes the cylinders to fire at uneven intervals and produces the choppy "potato-potato" sound so strongly linked to the Harley-Davidson brand.

To simplify the engine and reduce costs, the V-twin ignition was designed to operate with a single set of points and no distributor. This is known as a dual fire ignition system, causing both spark plugs to fire regardless of which cylinder was on its compression stroke, with the other spark plug firing on its cylinder's exhaust stroke, effectively "wasting a spark". The exhaust note is basically a throaty growling sound with some popping. The 45° design of the engine thus creates a plug firing sequencing as such: The first cylinder fires, the second (rear) cylinder fires 315° later, then there is a 405° gap until the first cylinder fires again, giving the engine its unique sound.[102]

Harley-Davidson has used various ignition systems throughout its history – be it the early points and condenser system, (Big Twin up to 1978 and Sportsters up to 1978), magneto ignition system used on some 1958 to 1969 Sportsters, early electronic with centrifugal mechanical advance weights, (all models 1978 and a half to 1979), or the late electronic with transistorized ignition control module, more familiarly known as the black box or the brain, (all models 1980 to present).

Starting in 1995, the company introduced Electronic Fuel Injection (EFI) as an option for the 30th anniversary edition Electra Glide.[103] EFI became standard on all Harley-Davidson motorcycles, including Sportsters, upon the introduction of the 2007 product line.[104]

In 1991, Harley-Davidson began to participate in the Sound Quality Working Group, founded by Orfield Labs, Bruel and Kjaer, TEAC, Yamaha, Sennheiser, SMS and Cortex. This was the nation's first group to share research on psychological acoustics. Later that year, Harley-Davidson participated in a series of sound quality studies at Orfield Labs, based on recordings taken at the Talladega Superspeedway, with the objective to lower the sound level for EU standards while analytically capturing the "Harley Sound."[citation needed] This research resulted in the bikes that were introduced in compliance with EU standards for 1998.

On February 1, 1994, the company filed a sound trademark application for the distinctive sound of the Harley-Davidson motorcycle engine: "The mark consists of the exhaust sound of applicant's motorcycles, produced by V-twin, common crankpin motorcycle engines when the goods are in use". Nine of Harley-Davidson's competitors filed comments opposing the application, arguing that cruiser-style motorcycles of various brands use a single-crankpin V-twin engine which produce a similar sound.[105] These objections were followed by litigation. In June 2000, the company dropped efforts to federally register its trademark.[106][107]

This is 100% correct. My concern was both rods sharing a common crank pin. One rod passes through the other. Seems to me like a lot of stress on that one crank pin. Obviously it works. Triumph Thunderbird as two pins but is staggered like Harley and sounds almost identical at idle.

It was foolish to try to trademark it's sound.

[cactusjack]

If you want a bike that sounds like a Harley, you could do as many of us have and go buy yourself a Harley.

[cnc]

Originally Posted by hayes

Good to know. I wish I could remember where I heard that. Oh well. No skin off my back. And people believe it, even the Harley riders. 😉

Yeah sounds plausible till you do a little geometry. I could not find any reference to the story even as an urban legend.

[ubernomad]

Originally Posted by cactusjack

If you want a bike that sounds like a Harley, you could do as many of us have and go buy yourself a Harley.

This isn't about "wanting" a Harley. I don't. I'm just curious why the metric V-twin engines sound nothing like a H-D engine.....from an engineering/design standpoint.

[macmac]

Originally Posted by glwilson

This is directly from Wikipedia; and is as an accurate description of why the sound is produced as one can explain. It is all here...
The classic Harley-Davidson engines are V-twin engines, each with a 45° angle between the cylinders. The crankshaft has a single pin, and both pistons are connected to this pin through their connecting rods.[9]

This 45° angle is covered under several United States patents and is an engineering tradeoff that allows a large, high-torque engine in a relatively small space. It causes the cylinders to fire at uneven intervals and produces the choppy "potato-potato" sound so strongly linked to the Harley-Davidson brand.

To simplify the engine and reduce costs, the V-twin ignition was designed to operate with a single set of points and no distributor. This is known as a dual fire ignition system, causing both spark plugs to fire regardless of which cylinder was on its compression stroke, with the other spark plug firing on its cylinder's exhaust stroke, effectively "wasting a spark". The exhaust note is basically a throaty growling sound with some popping. The 45° design of the engine thus creates a plug firing sequencing as such: The first cylinder fires, the second (rear) cylinder fires 315° later, then there is a 405° gap until the first cylinder fires again, giving the engine its unique sound.[102]

Harley-Davidson has used various ignition systems throughout its history – be it the early points and condenser system, (Big Twin up to 1978 and Sportsters up to 1978), magneto ignition system used on some 1958 to 1969 Sportsters, early electronic with centrifugal mechanical advance weights, (all models 1978 and a half to 1979), or the late electronic with transistorized ignition control module, more familiarly known as the black box or the brain, (all models 1980 to present).

Starting in 1995, the company introduced Electronic Fuel Injection (EFI) as an option for the 30th anniversary edition Electra Glide.[103] EFI became standard on all Harley-Davidson motorcycles, including Sportsters, upon the introduction of the 2007 product line.[104]

In 1991, Harley-Davidson began to participate in the Sound Quality Working Group, founded by Orfield Labs, Bruel and Kjaer, TEAC, Yamaha, Sennheiser, SMS and Cortex. This was the nation's first group to share research on psychological acoustics. Later that year, Harley-Davidson participated in a series of sound quality studies at Orfield Labs, based on recordings taken at the Talladega Superspeedway, with the objective to lower the sound level for EU standards while analytically capturing the "Harley Sound."[citation needed] This research resulted in the bikes that were introduced in compliance with EU standards for 1998.

On February 1, 1994, the company filed a sound trademark application for the distinctive sound of the Harley-Davidson motorcycle engine: "The mark consists of the exhaust sound of applicant's motorcycles, produced by V-twin, common crankpin motorcycle engines when the goods are in use". Nine of Harley-Davidson's competitors filed comments opposing the application, arguing that cruiser-style motorcycles of various brands use a single-crankpin V-twin engine which produce a similar sound.[105] These objections were followed by litigation. In June 2000, the company dropped efforts to federally register its trademark.[106][107]

I didn't respond since this covers 99%. Dead spark the firing order which is strange on the HD, the cams, the push rods versus over head cams. HD cams are totally different for the over heads, and i really doubt the jug angles make a bit of difference.

I also didn't know that HD were based off radial engines, and so were missing 8 clys. I see some have confused that to think time is spaced missing 8 clys.. it's not missing them in time, they just are not there but then the cams are not made for the 8 missing clys either.

Last I knew the HD connecting rod was one piece and carried 2 pistons.

And don't confuse rotary engines with radial. A vintage rotary engine has a fixed crank shaft, and the jugs all whirl about the fixed crank.

[macmac]

Radial not rototary. These turned OFF look similar but are nothing alike really.

[macmac]

So 'IF' the HD engines are take offs of radial engines they are missing some JUGS, but are camed for 2 jugs, but I do not 'KNOW' that as fact.

[OldSchool]

Originally Posted by hayes

The original hd was made from a 10 cylinder plane engine. You get that sound because the crank is still based of ten cylinders. You get fire on 1 then 2 but then you have 8 missing fires. That's the "hesitation" you're hearing.

I was told that by a Harley historian and it made sense. I have no idea if it's true, but I believe it...

V Twins were around way before airplanes ever flew.

http://en.wikipedia.org/wiki/V-twin_engine

[Sparks500]

I'm no mechanic, but, a few years back I read an article about this same thing. They did mention the simultaneous firing plugs and the fact that most, if not all, metric v-twins have 4 valves per cylinder compared to Harley's 2.
Harley's do have a nice sound, I'm just leery of an engine without an oil sump.

[a340driver]

Interesting ...

[macmac]

Originally Posted by Sparks500

I'm no mechanic, but, a few years back I read an article about this same thing. They did mention the simultaneous firing plugs and the fact that most, if not all, metric v-twins have 4 valves per cylinder compared to Harley's 2.
Harley's do have a nice sound, I'm just leery of an engine without an oil sump.

Dry sump works upside down, and so is no problem at all. This may have come to be in WW-1 for air planes but I don't know that is the reason. Porsche 911's had that system and maybe still do.