potato-potato

This round's on me Shirley.

Just curious about the sound my '07 dyna with stock pipes makes. It
does not seem to make that "potato-potato" sound I am normally used to
hearing (and was very evident on an '05 dyna that I test road).

Is this because of the stock pipes or is this due to the twin cam
engine?

Edward
'07 FXDL

Edward wrote:
> This round's on me Shirley.
>
> Just curious about the sound my '07 dyna with stock pipes makes. It
> does not seem to make that "potato-potato" sound I am normally used to
> hearing (and was very evident on an '05 dyna that I test road).
>
> Is this because of the stock pipes or is this due to the twin cam
> engine?

Higher idle rpm, I believe, because of the EFI.
If you ever get caught in no-go traffic on a hot day for a while, it
might automatically drop down, and Bingo... the 'tater sound is there.
Scared the fuck outa me when it happened, cause I thought something broke.

Edward wrote:
> This round's on me Shirley.
>
> Just curious about the sound my '07 dyna with stock pipes makes. It
> does not seem to make that "potato-potato" sound I am normally used to
> hearing (and was very evident on an '05 dyna that I test road).
>
> Is this because of the stock pipes or is this due to the twin cam
> engine?


It's probably the carbs.

"Edward" <edward_mcmasters@yahoo.com> wrote in message
news:12898030-2f7a-468d-83a2-e0f40842692d@s8g2000prg.googlegroups.com...
> This round's on me Shirley.
>
> Just curious about the sound my '07 dyna with stock pipes makes. It
> does not seem to make that "potato-potato" sound I am normally used to
> hearing (and was very evident on an '05 dyna that I test road).
>
> Is this because of the stock pipes or is this due to the twin cam
> engine?
>
> Edward
> '07 FXDL

In 05 you could still get a carb. Its obvious to me that you road a 05 for
you test.Your not going to get the same sound you heard out the 05
carburetor on your 07 FI. It can get close but still not the slow potato
potato sound.
--



Carl

I started out with nothing, and
I just about have that paid for.

Remove one 9 to reply



--
Posted via a free Usenet account from http://www.teranews.com

On Fri, 30 Nov 2007 08:18:43 -0800 (PST), Edward
<edward_mcmasters@yahoo.com> wrote:

>This round's on me Shirley.
>
>Just curious about the sound my '07 dyna with stock pipes makes. It
>does not seem to make that "potato-potato" sound I am normally used to
>hearing (and was very evident on an '05 dyna that I test road).
>
>Is this because of the stock pipes or is this due to the twin cam
>engine?
>
>Edward
>'07 FXDL

I haven't heard a real potato, potato sound since the shovelhead.

These days it take a pretty tall cam and some free flowing carb and
pipes to get close.
--
Bob Mann

Sex is like air; it's not important unless you
aren't getting any

"Bob Mann" <Bobo@nowhere.com> wrote in message
news:ehk1l3pt66ba95r199lh03kcmsbnrb6np7@4ax.com...
> On Fri, 30 Nov 2007 08:18:43 -0800 (PST), Edward
> <edward_mcmasters@yahoo.com> wrote:
>
>>This round's on me Shirley.
>>
>>Just curious about the sound my '07 dyna with stock pipes makes. It
>>does not seem to make that "potato-potato" sound I am normally used to
>>hearing (and was very evident on an '05 dyna that I test road).
>>
>>Is this because of the stock pipes or is this due to the twin cam
>>engine?
>>
>>Edward
>>'07 FXDL
>
> I haven't heard a real potato, potato sound since the shovelhead.
>
> These days it take a pretty tall cam and some free flowing carb and
> pipes to get close.
> --
> Bob Mann
>
> Sex is like air; it's not important unless you
> aren't getting any



Bingo! Shovels, pans were the spud machines. Back in the day the ticket was
to see just how slow you could get it to idle.

EVO's and Twinkies just dont have it. Modern technology has changed alot.


kgdb

On Sat, 01 Dec 2007 08:43:15 GMT, "kgdb" <chopper@chopper.com> wrote:

>
>"Bob Mann" <Bobo@nowhere.com> wrote in message
>news:ehk1l3pt66ba95r199lh03kcmsbnrb6np7@4ax.com.. .
>> On Fri, 30 Nov 2007 08:18:43 -0800 (PST), Edward
>> <edward_mcmasters@yahoo.com> wrote:
>>
>>>This round's on me Shirley.
>>>
>>>Just curious about the sound my '07 dyna with stock pipes makes. It
>>>does not seem to make that "potato-potato" sound I am normally used to
>>>hearing (and was very evident on an '05 dyna that I test road).
>>>
>>>Is this because of the stock pipes or is this due to the twin cam
>>>engine?
>>>
>>>Edward
>>>'07 FXDL
>>
>> I haven't heard a real potato, potato sound since the shovelhead.
>>
>> These days it take a pretty tall cam and some free flowing carb and
>> pipes to get close.
>> --
>> Bob Mann
>>
>> Sex is like air; it's not important unless you
>> aren't getting any
>
>
>
>Bingo! Shovels, pans were the spud machines. Back in the day the ticket was
>to see just how slow you could get it to idle.
>
>EVO's and Twinkies just dont have it. Modern technology has changed alot.
>
>
>kgdb
>
>
I think that lopey sound was part of the charm and also part of the
problem those bikes had (have).
The closer you get to that sound, the rougher it runs and the more it
shakes.
But, they do sound sweet.

--
Bob Mann

Sex is like air; it's not important unless you
aren't getting any

On Sat, 01 Dec 2007 08:43:15 GMT, "kgdb" <chopper@chopper.com> wrote:

>
>"Bob Mann" <Bobo@nowhere.com> wrote in message
>news:ehk1l3pt66ba95r199lh03kcmsbnrb6np7@4ax.com.. .
>> On Fri, 30 Nov 2007 08:18:43 -0800 (PST), Edward
>> <edward_mcmasters@yahoo.com> wrote:
>>
>>>This round's on me Shirley.
>>>
>>>Just curious about the sound my '07 dyna with stock pipes makes. It
>>>does not seem to make that "potato-potato" sound I am normally used to
>>>hearing (and was very evident on an '05 dyna that I test road).
>>>
>>>Is this because of the stock pipes or is this due to the twin cam
>>>engine?
>>>
>>>Edward
>>>'07 FXDL
>>
>> I haven't heard a real potato, potato sound since the shovelhead.
>>
>> These days it take a pretty tall cam and some free flowing carb and
>> pipes to get close.
>
>Bingo! Shovels, pans were the spud machines. Back in the day the ticket was
>to see just how slow you could get it to idle.

Shovels n' Pans, Pattoooey! My Knuck is where that original sound
came from... th' rest are alla buncha piss poor imitations.

Snarl

<snarl@trippin.com> wrote in message
news:uho3l3trlu01h5otn92arn1btd57jeqedf@4ax.com...
> On Sat, 01 Dec 2007 08:43:15 GMT, "kgdb" <chopper@chopper.com> wrote:
>
> >
> >"Bob Mann" <Bobo@nowhere.com> wrote in message
> >news:ehk1l3pt66ba95r199lh03kcmsbnrb6np7@4ax.com.. .
> >> On Fri, 30 Nov 2007 08:18:43 -0800 (PST), Edward
> >> <edward_mcmasters@yahoo.com> wrote:
> >>
> >>>This round's on me Shirley.
> >>>
> >>>Just curious about the sound my '07 dyna with stock pipes makes. It
> >>>does not seem to make that "potato-potato" sound I am normally used to
> >>>hearing (and was very evident on an '05 dyna that I test road).
> >>>
> >>>Is this because of the stock pipes or is this due to the twin cam
> >>>engine?
> >>>
> >>>Edward
> >>>'07 FXDL
> >>
> >> I haven't heard a real potato, potato sound since the shovelhead.
> >>
> >> These days it take a pretty tall cam and some free flowing carb and
> >> pipes to get close.
> >
> >Bingo! Shovels, pans were the spud machines. Back in the day the ticket
was
> >to see just how slow you could get it to idle.
>
> Shovels n' Pans, Pattoooey! My Knuck is where that original sound
> came from... th' rest are alla buncha piss poor imitations.
>
> Snarl
>
They did have that old JD tractor lope to them for sure! I do miss hearing
my Pan. If things work that way I'd like to take the trip to Milwaukee to
see it again.
--



Carl

I started out with nothing, and
I just about have that paid for.

Remove one 9 to reply



--
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"Ironhorse" <Ironhorse74@hotmail.com> wrote in message
news:khv3l39tb83gco6furep1uebth537vgnkd@4ax.com...
> On Sat, 01 Dec 2007 15:36:51 -0800, BigPiper <jb@mcneel.com> wrote:
>
> >
> >> I think that lopey sound was part of the charm and also part of the
> >> problem those bikes had (have).
> >> The closer you get to that sound, the rougher it runs and the more it
> >> shakes.
> >> But, they do sound sweet.
> >>
> >
> >I was amazed how slowly TNFH got the idle on his knucklehead and SNIFF
> >the year before last. It sat there with a wiggly, wobbly slow putter
> >that could not have been over 500 RPM. It was pretty cool.
> >
> But do you know why they go Potato Potato?
>
> Because of the common crank pin and the V arrangement of the
> cylinders. The pistons do not fire 360 degrees apart. The first one
> fires at 315 degrees and the second fires at 405 degrees.
>
>
> Ironhorse, AH#130, HSB#96, SENS BS#187
> 2001 Ultraclassic with Sidecar
> 96 Custom bucket of bolts (gone but not forgotten)
>
> Republicans think every day is 4th of July
> Democrats think every day is April 15th
> Ronald Reagan

Sense Brad brought it up I'll post the artical,,Kind of long but here is the
story.

Designing Sound Characteristics
Into a Motorcycle Engine
Joel Moser


Early on a cloudless July morning in America's Great Plains, a farmer,
clutching
his warm cup of coffee, walks toward one of his tractors as he begins his
work
day. Before he reaches his goal, he hears the crisp exhaust note of a
motorcycle, and out THE ART OF NOISE:
of the corner of his eye he notices a single headlight
cresting the hill of the U.S. Highway that runs adjacent to his field. Long
before the motorcycle gets close enough for him to read the name on the gas
tank, the farmer knows that he is sharing this early morning moment with a
rider
aboard a Harley-Davidson, simply because of what he is hearing.
The Harley-Davidson Motor Company has re-emerged as the leader in the
heavyweight motorcycle industry because of countless stories of concise
product
recognition similar to this one. While improving the quality of their
product
line, the Motor Company has remained faithful to the styling cues that it
was
built upon, and in doing so has created an identity by which the rest of the
cruiser genre is judged. Just what are some of these styling cues? Many of
them
are visual, like "Springer" front suspensions, peanut-shaped fuel tanks, and
finned V-twin engines. And some are audible, for as Jon Thompson explains,
"An
essential element of the H-D equation is the charismatic feel and sound of
the
Harley engine--a sound one Honda spokesman characterized as, no kidding,
'potato- potato-potato!' " (Thompson 44)
While this may not sound like the most flattering of descriptions, it is one
that Harley has embraced completely, and takes very seriously. It is a
cornerstone of their marketing strategy, for even their product guide
exclaims:
Potato, Potato, Potato. . . A Harley-Davidson at Idle. Has the wind ever
carried a more satisfying sound?...The sound is unmistakable. The
signature of
a Harley-Davidson motorcycle... you instinctively know: this is the way a
motorcycle ought to sound... This did not happen by accident... when we
find
something more pleasing than anything else, we stick with it. Like the
exhaust
note of a Harley-Davidson 45° V-twin, the sweetest sound ever carried on
the
wind.
Clearly, Harley believes that their V-twin exhaust rumble is instantly
recognizable and discernible to the trained ear, and believes that it is a
vitally important component of their strong product identity. Because of
this,
their design engineers are asked to create products that are technologically
competitive and yet wonderfully nostalgic -- essentially, they are asked to
design with an eye toward the future and an eye toward the looks and sounds
of
motorcycles long past.
Just how is an exhaust note designed to 'sound like a Harley?' What
parameters
govern such a design requirement? Answering these questions is an everyday
experience for some of the engineers at the Harley-Davidson Motor Company,
and
their effectiveness in garnering solutions to them help ensure their
product's
continued success in the marketplace.
Design Parameters
The exhaust rumble that is created by a running motorcycle engine is a very
complex sound, and it is one whose origin is equally complex. Beginning
before
the combustion process and ending with the muffling of the exhaust, the tone
of
the sound that is ultimately heard by the customer is one that has been
influenced by a great number of parameters. Many decisions are made with a
special cognizance of their effect on this tone, and when they are coupled
together the result is, according to Harley, "the way a motorcycle ought to
sound." While all of these design decisions contribute to this
characteristic
exhaust sound, only a small number of them are regarded as absolutely
essential
to it. Thus, a closer investigation of these critical ones is truly necessa
ry
in order to obtain a more complete understanding of the origin of this
styling
cue, this 'Harley sound.'
Carburation and Ignition. While one may intuitively think that tonal exhaust
characteristics begin with the combustion process, they actually begin to
evolve
even before that. As air and fuel mix in the carburetor and enter the
cylinder
on the intake stroke, these tonal qualities are being influenced and
developed.
This influence is a subtle one, yet it is one that is noticeable enough that
Harley's engineers must take it into account when citing the origins of
their
sound.
The typical modern motorcycle uses an individual carburetor for each of its
cylinders. This design increases overall engine performance, including
responsiveness and horsepower, and as a result virtually every motorcycle
imported into this country today includes a bank of multiple carburetors to
serve its intake needs. Harley-Davidsons, in contrast, use a single
carburetor
with a shared intake manifold to supply both cylinders with air and fuel.
Most
manufacturers consider this design to be rather dated, but Harley has chosen
to
stay with it for a number of reasons. These include a reduction in
complexity
and a cleaner visual appearance, as well as the creation of a noticeable
unevenness in the exhaust rumble. This final reason is due to the fact that
this
dual intake strongly affects the air/fuel pressure waves and their induction
into the cylinders, since varying pressure waves are forced to be
superimposed
on one another. A characteristic unevenness develops here because of this,
and
it continues all the way through the combustion and exhaust processes.
This unevenness is further accentuated by another of Harley's designs that
most
manufacturers would consider dated. While today's motorcycle manufacturers
typically use individual ignition coils for each of the cylinders in their
engines, Harley-Davidson continues to use only one coil to serve the needs
of
two cylinders. This means that the sparkplugs can not be controlled
separately
-- both plugs fire at the same time, regardless of whether it is that
cylinder's
combustion stroke or not. Thus, the sparkplugs in a Harley are firing twice
during a complete engine cycle -- once on the combustion stroke and once on
the
exhaust stroke. While one cylinder is beginning its combustion stroke and
sparking, the other is beginning its exhaust stroke and also sparking. This
spark on the exhaust stroke is known as a "wasted spark," (A. Bub) and since
there is a minute amount of unburned fuel in the exhausting cylinder, this
"wasted spark" creates a partial detonation. This partial detonation is
important not only from an emissions standpoint but also from an acoustics
standpoint, because it definitely contributes to exhaust unevenness.
Just how important is this slight unevenness to 'the Harley sound?'
Interestingly, it is lost in some of the new Harley-Davidsons, because of th
e
advent of fuel injection. These fuel-injected models sound very similar to
their
predecessors, but since they do not use these older designs just mentioned,
there is a subtle component missing. Subtle yes, but certainly still
noticeable,
and Harley has already heard of a case where a man asked to trade in his
brand
new fuel-injected model for a new carburated one, simply because his wife
said
it didn't sound quite right. (C. Moser)
Engine Architecture and Crankshaft Design. While the design decisions
surrounding the air/fuel induction into the cylinder are clearly important
to
creating unique tonal characteristics, it is the decisions surrounding the
combustion process that are of primary importance. In particular, the use of
a
single-pin crankshaft in a 45° V-Twin is perhaps the single most important
parameter to consider while trying to explain the origins of the 'Harley
sound,'
for this combination results in a unique engine timing diagram and a unique
elopeness that directly translate into the tonal characteristics that Harley
cherishes. This combination is no secret, for as Jon Thompson explains:
That characteristic sound and rhythm [of a Harley] is the result of both
connecting rods... being driven off of a single crankshaft pin. The
[Honda]
Shadow... has two crankpins, oriented 90° apart. That's a better way to
quell
the engine's dynamic forces, but it doesn't reproduce the sound of
nostalgia.
(Thompson 44)
This being the case, it should not come as a surprise that every model in
the
Harley lineup this year, as in years past, is based on a 45° V-twin with a
single pin crankshaft. Nor should it be surprising that when Honda engineers
developed their new American Classic Edition (ACE), a cruiser intended to
directly appeal to potential Harley riders, their "first change [for the
ACE]
was to adopt a single crankpin in a successful effort to capture the
traditional
American sound." (Thompson 44) Based on this new design, Tim Hoelter, vice
president and general council of H-D, was prompted to publicly accuse Honda
of
introducing an engine that purposely mimics the Harley sound. (Savage 1D)
As is the case with the carburation and ignition systems on a Harley, this
single crankpin design is a very old one. Harley has been using its "fork
and
knife" version of it since 1909, and no other manufacturers have
consistently
used the "fork and knife" since Indian and Vincent did in the 1950's.
(Bleustein
6) The fact that the majority of the industry has migrated to newer designs
is
not surprising, because the "fork and knife" is inherently weak due to
stress
concentrations in the outer connecting rod. These stress concentrations are
certainly a concern to Harley, but not enough to cause the company to
abandon
the design. In fact, Harley sees this design as a part of their heritage,
and
point to it as a link to their storied past. Such attention to history
breeds a
consistency in product evolution, and this evolution has greatly helped in
maintaining the familiar 'potato-potato- potato' sound.
Exhaust and Muffler Design. What other parameters are involved in creating
Harley's uniquely identifiable exhaust sound? While decisions involving
carburation and the use of a single-pin crankshaft are two of them, there is
certainly more to this formula. The exhaust and muffler assembly is also an
essential ingredient.
Harley-Davidson uses only three different muffler designs to serve the needs
of
all of their models. The first of these is a plug muffler and is used on all
of
the 883cc Sportster models built for the U.S. market. Another is also a plug
muffler for 883cc Sportsters, but it is used for models going to
international
markets. And the third design, a muffler internally similar to an automobile
muffler, is used on all of the 1340cc models regardless of product
destination.
The basic design of the plug muffler is an old one, but it is one that is
still
widely
accepted by the motorcycle industry as a whole. Essentially, as exhaust
gases
are pushed out of the cylinder and down the exhaust tube, they are forced
through a perforated screen and into a section of fiberglass, where the
majority
of noise reduction takes place. After moving through the fiberglass, the
gases
are forced through another set of holes and are then exhausted to the
atmosphere. Variations of this design are used worldwide for many
applications,
and Harley-Davidson has consistently used it to meet their needs as well.
Based on data obtained through years of testing, Harley engineers have
chosen to
use eight rows of holes in the section before the fiberglass in order to
optimize horsepower. They have also chosen to use either four rows (for
domestic
models) or two rows (for international models) of holes to the rear of the
fiberglass in order to optimize noise emission. All of this was done while
keeping in mind the overall goal of the muffler, which involved maintaining
the
frequency content in the noise emission that has become synonymous worldwide
with Harley-Davidsons. The tone of this frequency content, often described
as
'guttural,' is the result of the mufflers reducing the high frequencies
while
keeping the lower ones, and the fiberglass within the muffler section serves
this purpose splendidly. The result is the throaty 'potato-potato-potato'
sound
that the Honda spokesman described earlier.
But the plug muffler is not the only way to achieve this sound. The larger
motorcycles in Harley's line use a muffler design that is more car-like in
that
it uses a series of sharp internal bends to slow the gas flow and reduce
noise.
The resulting noise emission contains more of the higher frequencies, but
enough
reduction takes place that the tone is nearly identical to the tone of the
others. The only drawback to this design is that these tubing bends
necessitate
a larger diameter muffler, but this is regarded as an acceptable tradeoff
because the tonal quality of the exhaust still provides the ubiquitous sound
that Harley is known for.
Other Considerations
There are, of course, other sources that could be considered when
investigating
the origins of the 'Harley sound.' For example, one may think that the
design of
the camshaft may be important, since it is responsible for the actuation of
the
valves. This design is valid in that the camshaft affects the percentage of
time
that the exhaust valves would be open, or more importantly for this purpose,
closed. The timing of the valve closing determines the percentage of time
that
exhaust gas pressure pulses can move up and down the exhaust pipe with
closed-end termination on the engine side and the open atmosphere on the
other
side. These pulses move at a frequency that is certainly important to the
final
exhaust sound, (Munjal 105-107) but this frequency has been found to be a
function of the crankshaft and not of the camshaft. Because of this,
camshaft
timing is not critical to exhaust tonal quality, and Harley-Davidson has
been
able to use different camshafts in different applications without any
distinguishable change in the qualities of their exhaust.
Another source of noise that is not considered to be a large factor is what
is
known as "shell noise." This noise is generated by the exposed surfaces of
the
vibrating engine and mufflers and is due to the vibration characteristics
inherent to their operation. This noise is certainly not the primary
component
of the sound the customer enjoys, but it is a small part, and it is
something
that acoustic engineers worldwide are aware of. For example, at the 1995
Small
Engine Technology Conference in Milwaukee, engineers from Kawasaki presented
their research in this area, and demonstrated how it was now possible for
them
to predict the vibration mode and noise emission from their engine covers in
the
computer- assisted design phase. (Roadracing World 3) This research of
course
has no direct bearing on the shell noise characteristics of other
manufacturers,
but it certainly illustrates how this phenomenon can be a priority to an
engine
design team concerned with sound quality.
Conclusion
Because the Harley-Davidson Motor Company intimately understands the cruiser
genre of motorcycle, the company is currently enjoying an enormous amount of
commercial success. By focusing on style as well as function and by
incorporating nostalgia into modern technology, Harley has created a product
line that is admired by its customers and emulated by its competitors for
its
timeless qualities. These styling cues are numerous in number and varied in
nature, but taken as a whole they represent that which 'makes a Harley a
Harley.' A distinct exhaust sound is just one example of these, and this
closer
examination of the design parameters involved in such a requirement shows
just
how seriously Harley takes these styling cues. From the carburetor to the
muffler, design decisions are closely scrutinized to determine not only
their
performance, but also their impact on the visible and audible
characteristics of
the finished product. Such close scrutiny has led to strong sales, and this
type
of scrutiny is only now being employed by the other major manufacturers of
the
world. While the success of the competition's new models is yet to be
determined, one thing seems clear: unless they satisfy the customer's eyes
and
ears as well as Harley-Davidsons do, Harleys will continue to dominate this
segment of the motorcycle industry.
Works Cited
1. Bub, Alex. Project Coordinator--Powertrain Development, Harley-Davidson
Motor
Company. Personal Interview, 23 Dec 95
2. Bleustein, Jeffrey. "The Unique Harley-Davidson Sound." The Enthusiast,
Fall
'95. p.6
3. Harley-Davidson Motor Company. 1994 Product Guide. pp.3-4
4. Moser, Christopher. Mechanic. Personal Interview, 23 Dec 95
5. Munjal, M.L. Acoustics of Ducts and Mufflers New York: John Wiley and
Sons,
1987. pp. 104-108 & 285-296.
6. Roadracing World. "When Motorcycle Engineers Talk Shop." November 1995.
p. 3
7. Savage, Mark. "Harley Trademark Attempts Making Some Noise." Milwaukee
Journal Sentinel. November 2, 1995, latest edition. pp.1D - 3D
8. Thompson, Jon F. "1995 Honda American Classic Edition - Honda Hones the
Harley Formula" Cycle World. September 1994. pp. 44-45
Works Consulted
1. Elkins, Charles. "Environmental Impact Statement for the Noise Emission
Regulations for Motorcycles and Motorcycle Exhaust Systems" U.S. EPA Office
of
Noise Abatement and Control. December 1980
2. Stermer, William. "No Cliche Cruiser." Rider, November 1995, pp. 25-2




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