Topic: Velocity stacks tuning

[Dirk D]

I just bought some velocity stacks for my 1971 Honda CB500 and was wondering if I had to re jet the carbs. Everything is stock except for a Kerker exhaust.

[mlinder]

Answer: Yes.

[gnarlycharlie4u]

Answer: Yes.

+1

[Coyote13]

Wow. Not trying to hate, or sound like a dick, but you have a LOT of research to do

[Retro Rocket]

Everything is stock except for a Kerker exhaust.

Then why are you using stacks..?

[gnarlycharlie4u]

Everything is stock except for a Kerker exhaust.

Then why are you using stacks..?

I think the real question is... why didn't you just lose the airbox and use the carb to airbox mounts?
those are stacks and even have a little lip on the inside to mate right flush up to the carb intake.

[Dirk D]

Everything is stock except for a Kerker exhaust.

Then why are you using stacks..?

Because I got some NOS ones for cheap. Plus I think like most people on this forum I can't keep from wanting to change and mess with my bike as much as possible.

[Retro Rocket]

What do you mean NOS.? standard Honda ones that go between the carb and airbox.? The best your stock bike will run is with the syock airbox and a good quality filter, velocity stacks are designed for racing and work well at high RPM's, absolutely no need to put them on a stocker.....You any good at setting up carbs.? thats the next step and i doubt it will run that well with out filtering...

[gnarlycharlie4u]

What do you mean NOS.?

HOLY #$%* HE DID PUT THE AIRBOX BOOTS ON THERE!!!

[Dirk D]

Thanks for all the input guys. Maybe I won't end up using them. BTW. NOS is new old stock referring to any item that is not made any more but never been used. It doesnt have anything to do with a stock or factory item. Thats just incase you weren't being sarcastic. I'm not on this forum much so I don't know what terms are thrown around on here.

[gnarlycharlie4u]

Thanks for all the input guys. Maybe I won't end up using them. BTW. NOS is new old stock referring to any item that is not made any more but never been used. It doesnt have anything to do with a stock or factory item. Thats just incase you weren't being sarcastic. I'm not on this forum much so I don't know what terms are thrown around on here.

yea i think we just assumed you meant NOS Honda.

[Tintop]

You haven't said who's NOS stacks your using.  If it is the Honda ones, you want to use two sets of the 2/3 stacks, as the 1/4's are bent to fit the plenum.  Then add some foam filter socks (make sure to oil them), and zip tie in place.  Doing this won't change the tuned intake track length, and result in jetting problems.

Regarding jetting, I use the following to get close, then fine tune from there.

Exhaust change - up one main jet size.  If this isn't needed then that exhaust isn't anymore efficient than the stock, wasted $'s.
Air filter change - up one, possibly two depending on the setup.  Putting a K&N in the stock air box would be a one.  Anything else is probably going to require more.
Exhaust, and filter change - two sizes for sure, most likely three for the combination.  The slow jets may need an increase in size as well.

[shizzomynizzo]

I've got some stacks on my 550 project. No real engine work other than a 650 cam, and replica yosh exhaust.

I have some uni filter material I am putting in them (oiled) and then using booties to secure them in there.

Stacks look awesome, and I was hoping they would be easier than pods to tune. 

I'll let you know how it goes when I complete it in the next month or so

[Tintop]

I've got some stacks on my 550 project. No real engine work other than a 650 cam, and replica yosh exhaust.

I have some uni filter material I am putting in them (oiled) and then using booties to secure them in there.

Stacks look awesome, and I was hoping they would be easier than pods to tune. 

I'll let you know how it goes when I complete it in the next month or so

When you say 'in them', do you mean literally in the stacks?  This would significantly disrupt & restrict air flow.

[seanbarney41]

Thanks for all the input guys. Maybe I won't end up using them. BTW. NOS is new old stock referring to any item that is not made any more but never been used. It doesnt have anything to do with a stock or factory item. Thats just incase you weren't being sarcastic. I'm not on this forum much so I don't know what terms are thrown around on here.

yea i think we just assumed you meant NOS Honda.

I think, and like to use, the correct term NORS, new old replacement stock

[seanbarney41]

You haven't said who's NOS stacks your using.  If it is the Honda ones, you want to use two sets of the 2/3 stacks, as the 1/4's are bent to fit the plenum.  Then add some foam filter socks (make sure to oil them), and zip tie in place.  Doing this won't change the tuned intake track length, and result in jetting problems.

Tintop, do you have a pic or a link of these foam filter socks?

[Tintop]

I have used these in the past in other applications; a very good quality, multi layered product.

http://www.pipercross.net/competition/products_socks.asp  Note there are less expensive single layer ones available, but their filtering capabilities are not as good.

[shizzomynizzo]

I've got some stacks on my 550 project. No real engine work other than a 650 cam, and replica yosh exhaust.

I have some uni filter material I am putting in them (oiled) and then using booties to secure them in there.

Stacks look awesome, and I was hoping they would be easier than pods to tune. 

I'll let you know how it goes when I complete it in the next month or so

When you say 'in them', do you mean literally in the stacks?  This would significantly disrupt & restrict air flow.

Yes, In them. this will ensure I get no dirt in the engine. I don't want it to die a premature death.

I think it will restrict them a bit, but it will still be better than pods.

[TwoTired]

I think it will restrict them a bit, but it will still be better than pods.

Aren't dreams wonderful?

It's so nice to actually escape reality.   

[Retro Rocket]

I've got some stacks on my 550 project. No real engine work other than a 650 cam, and replica yosh exhaust.

I have some uni filter material I am putting in them (oiled) and then using booties to secure them in there.

Stacks look awesome, and I was hoping they would be easier than pods to tune. 

I'll let you know how it goes when I complete it in the next month or so

When you say 'in them', do you mean literally in the stacks?  This would significantly disrupt & restrict air flow.

Yes, In them. this will ensure I get no dirt in the engine. I don't want it to die a premature death.

I think it will restrict them a bit, but it will still be better than pods.

Sorry Shizzo but that completely defeats the purpose of having them in the first place. Put the foam boots on or the stacks with foam in them will be useless, it stops the stacks from doing what they are designed to do......

[Tintop]

I think it will restrict them a bit, but it will still be better than pods.

Aren't dreams wonderful?

It's so nice to actually escape reality.   

  - thanks TT, that's my smile for the day.

[phil71]

Wow, people are fed up with pod/velocity stack talk.
I'd just like to point out that, like you, everyone here has probably owned a bike that came with them, or attempted to use them because they look cool (thet do) , or someone handed down a set for free.
"It's not you, it's us".. I'd wager that 90% of the members here have chased erratic running conditions with pods/stacks only to eventually re-install a stock airbox with a better filter.
It's your turn to chase the dragon my friend, but you may only find snark and derision in the forum. There are some good older threads about some good starting points for jetting, but without a dyno and an exhaust gas analyzer, it's all trial and error.

[gnarlycharlie4u]

Wow, people are fed up with pod/velocity stack talk.
I'd just like to point out that, like you, everyone here has probably owned a bike that came with them, or attempted to use them because they look cool (thet do) , or someone handed down a set for free.
"It's not you, it's us".. I'd wager that 90% of the members here have chased erratic running conditions with pods/stacks only to eventually re-install a stock airbox with a better filter.
It's your turn to chase the dragon my friend, but you may only find snark and derision in the forum. There are some good older threads about some good starting points for jetting, but without a dyno and an exhaust gas analyzer, it's all trial and error.

you can probably get a lambda sensor for about $80. but honestly you'll still be fine just doing a plug chop on a good hill.

To be perfectly honest though... without engine mods or exhaust changes, those stacks really aren't worth running.
you won't see much if any power difference, and you'll lose some low end torque.

[shizzomynizzo]

Well on the bright side the carbs are much easier to remove with stacks, I won't mind trying to tune them.

I am going more for looks on this bike. If it runs like crap and I can't fix it, I'll put it up on CL like everyone else 

[gnarlycharlie4u]

Well on the bright side the carbs are much easier to remove with stacks, I won't mind trying to tune them.

I am going more for looks on this bike. If it runs like crap and I can't fix it, I'll put it up on CL like everyone else 

yea those stacks + "cafe racer" in the title and you can sell it for $2000 more than you paid. EASY