Velocity Stacks

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jdpan
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Velocity Stacks

#1

Post by jdpan » Tue Jul 19, 2011 11:39 pm

I've always dug the look of velocity stacks... A buddy machined an adaptor to fit an S&S stack to a four bolt Linkert. Pretty much just for show but looks wicked as hell! If you run one or have any cool pics, lets see em!

Image



fourthgear
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Re: Velocity Stacks

#2

Post by fourthgear » Wed Jul 20, 2011 3:04 am

Yes they look cool , but will not help the life of the motor . A filter will .

Cotten
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Re: Velocity Stacks

#3

Post by Cotten » Wed Jul 20, 2011 3:55 pm

JdPan!

Here's the real thing, on Liberty's Service Desk.

....Cotten
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Bosheff
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Re: Velocity Stacks

#4

Post by Bosheff » Wed Jul 20, 2011 4:03 pm

Had an old ridin bud of mine dump a Sporty over in the sand with a velocity stack on it. It was the perfect vacuum cleaner. Motor went from fresh to junk in a matter of seconds. Upon restartin after the fall, you could see the raw oil runnin from the drag pipes....bosheff

jdpan
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Re: Velocity Stacks

#5

Post by jdpan » Wed Jul 20, 2011 4:14 pm

Cotten, neat little desktop trinket there.... I looked around for one of those to no avail.

Bosh, sorry to hear about your buddy's Sporty, but I gotta tellya, this, "It was the perfect vacuum cleaner." kinda made me chuckle.. :lol:

kitabel
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Re: Velocity Stacks

#6

Post by kitabel » Wed Jul 20, 2011 10:29 pm

Some reduce air flow, only the best are better than nothing.
According to Vizard's extensive testing, the best is a shallow taper ending in a 3/4 curl-over radius at the open end, which may add as much as 5-7%.

Cotten
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Re: Velocity Stacks

#7

Post by Cotten » Thu Jul 21, 2011 2:37 am

Kitabel!

I am totally clueless about Vizard.
Is that a web handle?

Are his studies on line for download?

....Cotten

FlatHeadSix
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Re: Velocity Stacks

#8

Post by FlatHeadSix » Thu Jul 21, 2011 3:56 am

Bosheff wrote:It was the perfect vacuum cleaner. ....bosheff
and they will vacuum just about anything, they are particularly fond of loose fitting pants legs..

mike

and Cotten, how fast have you gotten the prop going on that Indian Mystery Stick? I'm sure you've rigged up some kind of tachometer to measure the rpm! I think it makes a difference if you rub them with an aluminum push rod or a solid steel one. :P

amiabledave
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Re: Velocity Stacks

#9

Post by amiabledave » Fri Jul 22, 2011 12:35 am

David Vizard's Carburetor books, he talks about a multitude of carburetors and his book on How to Build Horsepower. I never saw or read anything on motorcycles...There may be one out there.....Plus Velocity Stacks, as I understand them, won't do anything at idle and low rpm, But only when you start really moving air (drag racing mode) Is that what your going to do, drag the bike? Nice picture, but you'll go farther with a filtered carb.

jdpan
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Re: Velocity Stacks

#10

Post by jdpan » Fri Jul 22, 2011 12:45 am

"Pretty much just for show but looks wicked as hell!"

kitabel
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Re: Velocity Stacks

#11

Post by kitabel » Fri Jul 22, 2011 4:29 am

The best use is where the carb is too small for the engine, but sitting across the air-stream won't work.
The horn should be in still air, like inside a big empty box with a opening to the atmosphere. The opening should be larger than the velo ID, but smaller than the box's area.

jdpan
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Re: Velocity Stacks

#12

Post by jdpan » Fri Jul 22, 2011 4:55 am

I would imagin having a stack positioned like the one pictured could actually be counterproductive. As the air flowed accross the opening, it would actually creat a negative pressure in the venturi, possibly jacking with mixture settings on the carb at higher speeds.

Cotten
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Re: Velocity Stacks

#13

Post by Cotten » Fri Jul 22, 2011 1:44 pm

FlatHeadSix wrote: and Cotten, how fast have you gotten the prop going on that Indian Mystery Stick? I'm sure you've rigged up some kind of tachometer to measure the rpm! I think it makes a difference if you rub them with an aluminum push rod or a solid steel one. :P
Mike!

I no longer have access to a strobe tach.
Indians had pushrods?

Back to stacks,
mine is two double-shots.

....Cotten

FlatHeadSix
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Re: Velocity Stacks

#14

Post by FlatHeadSix » Fri Jul 22, 2011 4:09 pm

Indians had pushrods?....Cotten

I think the only true Indians that came with pushrods were the infamous Indian Arrows, but that's another sad chapter in Indian's history book, and best left alone.

mike

Cotten
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Re: Velocity Stacks

#15

Post by Cotten » Fri Jul 22, 2011 5:08 pm

FlatHeadSix wrote:Indians had pushrods?....Cotten

I think the only true Indians that came with pushrods were the infamous Indian Arrows, but that's another sad chapter in Indian's history book, and best left alone.

mike
Mike!

I guess my Chief does have pushrods, but they are what many might call tappets. I wonder how many laps aluminum would last at eight thou of lash.

....Cotten
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