Author Topic: velocity stacks  (Read 2288 times)

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Offline kranta

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velocity stacks
« on: December 09, 2015, 04:03:44 AM »
so i am going to buy velocity stacks to my 500 four. but i have read bad sides and good sides of them so. is it real worth of uprage? what are good sides and what are bad sides?

Offline Retro Rocket

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Re: velocity stacks
« Reply #1 on: December 09, 2015, 04:32:54 AM »
Your bike comes standard with velocity stacks, the only down side to aftermarket stacks is if you run them without filters and suck in dirt and crap... Your bike will always run better with velocity stacks than without.
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Offline flybox1

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Re: velocity stacks
« Reply #2 on: December 09, 2015, 08:10:54 AM »
Good:  They look kewl  8)
Bad: Alone, they will not make your bike faster or run better. 
They'll make your bike run like crap until you take the time to re-jet your carbs
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

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Offline kranta

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Re: velocity stacks
« Reply #3 on: December 10, 2015, 02:12:14 AM »
Ok. But doesnt the old fact matter on these honda fours? That more air is more fuel =more HP?

Offline seanbarney41

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Re: velocity stacks
« Reply #4 on: December 10, 2015, 02:26:51 AM »
The airbox supplies more than enough air for your engine.  It is not a restriction, and already incorporates velocity stacks.  The restriction is inside your cylinder head.
If it works good, it looks good...

Offline Dimitri13

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Re: velocity stacks
« Reply #5 on: December 10, 2015, 02:42:39 AM »
I ran stacks on mine for a while. Could never get them tuned right but they sounded and looked cool.

Offline carnivorous chicken

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Re: velocity stacks
« Reply #6 on: December 10, 2015, 06:30:54 AM »
Bare velocity stacks will allow dust and dirt and debris into your engine. Be ready to rebuild it frequently. You're not going to get any extra HP from simply switching to velocity stacks, you'll need to do a whole lot more to your bike. You'll get less HP and your bike won't run very well.

Offline DaveBarbier

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Re: velocity stacks
« Reply #7 on: December 10, 2015, 07:00:42 AM »
If you look inside a K&N pod you'll see that they have a radius formed into the rubber to help smooth and accelerate the air going into the carbs. If you're set on removing the airbox this might be a better option. There are also velocity stack boxes which have filter media around them. I've seen pictures of them around here and people who run them seem to like them.

Also, you're probably looking at Steel Dragon stacks? I don't know how well they perform as velocity stacks as the bell mouth isn't extreme and I think the ID of the stack is slightly smaller than the ID of the carb mouth (from what I've heard) which would result in turbulence kind of negating the purpose of the stack to begin with.

I have them though on my 550 with screens in them...for the sake of transparency. ;)

Offline flybox1

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Re: velocity stacks
« Reply #8 on: December 10, 2015, 07:13:03 AM »
Ok. But doesnt the old fact matter on these honda fours? That more air is plus more fuel =more HP?
FTFY
If that statement were so, every hipster bike would have v-stacks the size of beer cans  ;D
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline evanphi

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Re: velocity stacks
« Reply #9 on: December 10, 2015, 10:54:54 AM »
Ok. But doesnt the old fact matter on these honda fours? That more air is plus more fuel =more HP?
FTFY
If that statement were so, every hipster bike would have v-stacks the size of beer PBR cans  ;D

--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
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Offline Gene

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Re: velocity stacks
« Reply #10 on: December 10, 2015, 11:22:45 AM »
40 ozer stacks . . . now we're onto something.
*1973 CB750K3 (Bow)

Offline flybox1

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Re: velocity stacks
« Reply #11 on: December 10, 2015, 12:17:51 PM »
Ok. But doesnt the old fact matter on these honda fours? That more air is plus more fuel =more HP?
FTFY
If that statement were so, every hipster bike would have v-stacks the size of beer PBR cans  ;D

FOSTERS
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline Dimitri13

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Re: velocity stacks
« Reply #12 on: December 10, 2015, 12:28:49 PM »
Ok. But doesnt the old fact matter on these honda fours? That more air is plus more fuel =more HP?
FTFY
If that statement were so, every hipster bike would have v-stacks the size of beer PBR cans  ;D

FOSTERS

Australian for #$%*.

Offline Retro Rocket

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Re: velocity stacks
« Reply #13 on: December 10, 2015, 02:14:13 PM »
Ok. But doesnt the old fact matter on these honda fours? That more air is plus more fuel =more HP?
FTFY
If that statement were so, every hipster bike would have v-stacks the size of beer PBR cans  ;D

FOSTERS

Australian for #$%*.

Close, Australian for Laxative.... I don't actually know one Aussie that drinks Fosters, being one of the beer drinking capitols of the world, thats got to tell you something... ;D ;).....
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline carnivorous chicken

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Re: velocity stacks
« Reply #14 on: December 10, 2015, 03:39:44 PM »
I should add: in my experience, CB550s seem to take pretty well to pod filters, depending on the type. They're not CV carbs, and there are some adjustments to jet size and needle position that can smooth out the transition.

Offline PeWe

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Re: velocity stacks
« Reply #15 on: December 11, 2015, 04:34:19 AM »
You can use stacks AND pods. I have seen on a forum where they have made it, maybe a Kawasaki forum, Mikuni carbs.
My carbs have stacks (filter adaptors) for pods delivered from the beginning.

EDIT: Here is one example, I have seen other examples too
http://forums.kz650.info/index.php?PHPSESSID=ea1cc35dccabeafc0f9ba92e390b35ca&topic=3189.msg28364#msg28364
« Last Edit: December 11, 2015, 04:38:19 AM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline bwaller

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Re: velocity stacks
« Reply #16 on: December 11, 2015, 05:35:04 AM »
That's a nice solution PeWe. Proper bellmouth velocity stack design is a tad complicated, or at least for a stack that has potential to increase induction flow, even without consideration of any filter attached. I think most people agree they simply use "stacks" for the polished look or intake roar. From my limited experience, at least some of these are a step backwards and part of the reason twotired stepped aside!

Offline PeWe

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Re: velocity stacks
« Reply #17 on: December 11, 2015, 11:39:41 AM »
........ part of the reason twotired stepped aside!

Forum member TwoTired?  I have not seen him on the forum for a long time. He had very interesting, very detailed technical explanations and discussions that a forum like this need.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967