Velocity Stacks With Screens

Anyone got a source for velocity stacks WITH screens. Everything I've found is without. (And, yes, I have searched this forum already.)

Much obliged.

 

I've got some I'm not using. What size opening are you trying to fit?

 

Screens will still let in the fine beach sand you find when crashing at places like Roebling and Jennings

 

Tash got me a set of these stack booties and they work awesome. they come in just about any color you want and have an elastic band around them. they stretch tight around the end of your stacks. i also put a big a big zip tie around just because i'm O.C.D.

i believe they came from Fisher Buggies

 

I've learned to not use open carbs or stacks, couple of discoveries:

While tearing down motors, crystalized sand on top of the pistons.

And the biggie.....

On the Dyno at BoreTech, I made more power WITH those K&N's that Perinthian recommended than with an open stack.

Those booties have to help some, and Walkers sharp enough to realize that......Tash using them says something as well.

Plus, I kinda like the flattracker look of those filters.....no BS on the dyno.

 

Many thanks, guys. Patman, I will send you a PM about the stacks. Walker, I really like the booties idea, especially if I can't find screens. Charlie, what K&Ns are you referring to, the pod style? Those would be fine, too, but I'm shooting for the Wes Cooley look for my GS1000 and REALLY like the looks of the stacks he ran.

 

R5...no, not the little pods. I dont remember the number, but they are larger....think like hanging off an XR750 flattracker....probably a little large for what you are trying to do.....but I was an "Open Carb" guy for a long time....CP talked me into trying them, then the dyno results made me a believer.....I'm sure you will come up with something that works for you.....good luck.

 

Rick, i gave up looking for screens when I saw Tash's carbs. i like the bootie (yes, i do...) setup and can't tell any difference in air flow with them on.

 

Thanks for all the info, guys. Looks like Dynomanperformance.com is going to be able to provide the stacks, probably without screens, so booties it is!

 

I found a set of 4 in the shop that measures about 49mm i.d. Velocity stack with a bronze looking screen on the tops

 

Just emailed Mike at steeldragonperformance and they can custom make them for any bike. Very cool machined billet, with screens and good prices!

http://www.steeldragonperformance.com/products_2.html

 

V stacks arrived from steeldragonperformance.com. Very nice quality with brass screens and three set screws. Great price, too. I believe Mike can make them for just about any bike and in any reasonable length.

 

Don't want to sound silly but what are this "screens" and booties do lads?
Can you run without an airfilter if they are fitted?
Also, what do custom velocity stacks improve and how do you determine what lenght they should be?
Sorry, never came accross this mods before.
If some one could give me as much info as they have on the whole velocity stacks and screens mods I'll be forever greatfull.
Thank you.

 

Also, can this set up be used on bikes with ram-air, I.e. CBR600 F3?

 

I won't pretend to understand how velocity stacks work or how to calculate the optimum length for the desired effect, but if you do a search online you'll find some sites that are informative and at least one with a calculator. I understand that the bell shaped inlet is important in smoothing the air flow. The brass screens act as a primary filter and the "booties" as a secondary, finer filter. I've heard of folks using panty hose, but I'm not sure I'll try that. Regarding your second post, I don't know about your bike, but I have seen providers selling aftermarket stacks for modern bikes, I'm presuming so you can tune the intakes for the desired low end or high end performance. Someone will probably be along to explain all this much better, so stay tuned.

 

Carefull about making blanket statements that what worked well in one application will work for all. I have never seen a screened filter that doesn't flow less on a flow bench. Just compare the filter area of a 2" screen versus an airbox airfilter! Charlie, what spec engine in what state of tune are you refering to? I use open carbs, and open stacks, in most roadracing applications, and have no problems. I have never seen sand on pistons, only erroded valve seats with long-run engines.

 

does your bike have ram air system mate?

 

Stan, the motor I run the filters on is a full-on V1 motor, the motor I broke a crank in at Daytona this year...actually Eric Cooks / Steve-o's old bike....Woody Kyle head.

The sand was a different motor (earlier in time). I believe the sand came from riding the bike to a pit area around the back of Jennings....thru sand....or a crash I had at Jennings.....not just a "racing on the track normal use" thing.

Initially, after the sand thing, I started thinking about filters for crash's, etc....theres alot of sand down here (Daytona, RR, Jennings), especially when your bike is sliding on its side.....I was thinking "precautionary" at the time, but...

I Decided to utilize them on this new motor, especially for Daytona, so I decided to tune for them on the dyno.....and they worked surprisingly well.

Another point is I have Buffs stacks inside the filters. I had to cut the top of the filter to insert the stack, and then glued green foam on the end.

Initially, it was Perinthian and the green monster that used the system...I just copied it, then proved it to myself with the tuning.

I'm pretty sold on it, they are BIG K&N filters, not little pods...like flattrack filters, they tuck right in nice if you are not running a battery.

Your thoughts sir?

 

Stan:
A little off the thread but I would like to run filters on a new cylinder porting/head configuration on our 400. As you know, not much room behind the carbs on a RD especially when you install large body carbs. Have you ever tried the filter fabric like Tash uses on one of your two-strokes? I'd like to use a K&N but would have to crush it to get it in the space. Building a still air box that would allow jetting changes is beyond me.
Lyn Garland

 

Charlie,
You are right on track to use a large filter, with a big air space behind the carb, if your personal preference is to use a filter. If your dyno testing has shown a consistent improvement in power from any mod or part, I say go with it.

As a side note, I had a conversation at Vintage Days last week, with a fellow CB350 rider, who tuned his bike on a dyno with a well known tuner. The rider said that they found more power with a certain setup. I asked, "How many runs did you do before making changes?" He said, like two runs. I pointed out that these engines don't even get up to full temperature, and full power, unless you do about six pulls. "What did the Gas analyzer say?" "What's that?", he said. My point is, I won't believe any tuning advice, unless I question the operator and the details of the testing.

Lyn,
You are MY two stroke tuning guru, and I should be asking YOU for the tuning advice! Ha Ha!

Sorry, I haven't tried the filter fabric. My thoughts are to imitate the TZ's and run open carbs. Of course, the piston port engines will have substantial "misting" behind the carbs, at lower RPMs, and you don't want to get a filter saturated with excess fuel in the way. I'm not sure about the reed valve engines. I will be testing VM32s, and VM34s soon on my RD400, with the Sudco Banshee boots, and if you want me to try something, just let me know!

Andrei,
You have a good airbox, with built-in velocity stacks already on the F3, that will work very well with or without ram -air. Get the most free-flowing filter in the stock airbox location.

Stan