Pod Filters?

You guys have all climbed way out on the wrong branch of the tree.

It's not about turbulence; it's about finite vs. infinite air supply and its effect on VELOCITY.

CV carbs=constant VELOCITY. The reason that putting the airbox boots back on works is because they perform the same function as...

VELOCITY STACKS. There's a reason they call them that. Racers don't run wide-open carbs, they run velocity stacks. For a reason; even on non-CV carbs.

Debate the how all you want; the science is all about air velocity. And smoothing out any inherent turbulence probably does help increase velocity.

 

Thanks fitz, all I really know for SURE about carburators and tuning is that putting the boots on my pods helped me. I know that for a fact. Otherwise, I am still learning from ALL that is posted on this website.

 

Whether you call it "turbulence" or not, the simple fact is (as pointed out in MANY other threads) that pod filters alone do not shape the air charge coming in to the intake horn on the carburetor. Also, as a result of basic fluid dynamics, air being pulled from an infinite source (see above post about the common atmosphere in the stock airbox) has a tendency to vortex. It also enters the carburetor at a reduced velocity, which is critical to getting the CV slide to operate properly. The oval shaped orifice on the top of the carb intake horn supplies the air necessary to lift the CV slide, allowing the proper amount of air and fuel to enter the venturi through the emulsion tube. This oval shaped opening requires a positive pressure atmosphere to function properly, which is supplied by the shaped air charge coming through the velocity stacks or through the stock airbox boots. The vortex air stream created by pods, while not technically turbulent, inevitably produces a negative pressure atmosphere behind the CV slide air opening, which in turn reduces the proper function of the slide, which results in a nearly impossible to correct ultra-lean condition. In short, pods can be used, but if you want to protect your engine then there MUST be some sort of tube between the pods and the carbs to provide a shaped, high-velocity charge of air to the carbs. After over a year of trying to dial in with only pod filters (for some reason there isn't room on my bike for velocity stacks) I have ordered a stock airbox to reinstall on the bike. Just my $0.02

 

im not really interested in debating the pods vs airbox anymore, i was just tired of seeing "pods create turbulence" posted everywhere. important to the debate or not, that myth needs to die.

 

swguy270.

The Oval Orifice at the Top of the Intake Horn is an Atmospheric VENT.
That VENT is the sole supply of AIR to:
>>The Pilot AIR Jet
++The ==> MAIN <== AIR Jet.

The Lowering of Pressure at the VENT Opening robs the Main AIR Jet of the supply of AIR needed to surround the EMULSION Tube.

Without that AIR supplied to surround the Emulsion Tube and be drawn-up into the Intake Air with (and) atomizing the Fuel.

The Carb just don't work right.
Cant.
Needs air.

 

Ok so I had the dynamics backward. Thanks for the clarification, Rick. So the orifice provides air to the pilot and main air jets and does not provide the pressure necessary to raise the piston. I must be dyslexic. i am apparently understanding things backward. Thanks again. I had for some reason formed the idea that the lack of airflow through the emulsion tube was a result of the slide not receiving the proper vacuum signal. BTW just so everyone knows, I have absolutely NO problem being corrected when I make such a mistake. Please do, in fact. This is how we learn.

 

You had it right.
Your explanation of the lowering of pressure at the Orifice Opening was the Critical part of the deal.

Additionally, the lowering of pressure at the Orifice reduces pressure within the Atmospheric Chamber BELOW the Rubber Diaphragm.
>>Making it more difficult for the Diaphragm to collapse, ... causing the Piston to NOT rise as efficiently as it should.

Until recently, ... the only way to deal with the LEAN Condition resulting from Pods was Shims and Re-Jetting.

Now, understanding that the Intake Horn of the Carb NEEDS a Shaped and Accelerated Volume of AIR at the Intake:
> Experimentation on Manifolds and Internal Velocity Stacks has been initiated by Forum Members.

We've done more to solve the Pod Dilemma in the past 18-Months than all the Shim and Jetting Sites have done in over 25-Years.

Personally, I think the "Orifice Bypass" I conjured-up, by blowing smoke rings at a Carb hooked-up to a small Shop vac, ... will help solve both the LEAN and POWER BAND Issues, in short order ... once someone tries affixing a Cover Plate to the Atmosphere Orifice and Drilling a Bypass Hole atop the Intake Horn.


(PHOTO: Mikuni Intake Horns. Hitachi Carbs similar.)

 

Has anyone heard of taking the bike to a Dyno and have it professionally tuned? I mean if you are banging your head against the wall trying to tune it yourself, why put yourself through the aggravation?

 

Cause we're modders here Taking it to a Dyno would take all the fun out of DIY.
Just IMO
I'm interested to see how the drilling and orfice blocking will work! Be nice to have another set of carbs
-Chris

 

I'm looking forward to hearing the results of someone who modifies their Carbs with the "RickCoMatic Bypass".

I feel certain that a large percentage of the Lean Condition will be improved upon, once some AIR is presented to the AIR Jets to improve the quantity of Fuel drawn-into the Engine via the Main Jet through the Emulsion Tube.

I think the Diaphragm Piston will lift better and Main Jet Fuel will be supplied in a manner closer to Normal than without the Bypass when outfitted with Pods.

 

I can certainly see where that would make a difference. Its not a risk either, provided that the plug in the orifice is temporary and a way can be found to filter the bypass hole. I don't suppose pulling particulates into the carb through the bypass hole would be a very healthy thing. I may try and see. The risk is removed because the mod could easily be reversed by removing the plugs and filling in the bypass hole with either hot lead or JB Weld or a similar product.

 

Ya, the rickomatic bypass will have to be filtered right, what if you tie all the holes together with a mainfold of some type, and run a mini pod like we podders run on the crank vent?

I would be willing to give the rick co hole a try on my carbs come spring, for sure. If the hole is threaded it would be easily blocked by a set screw. Only real thing to figure out is the block off plate inside on the carb.

 

I would make the Bypass Hole just large enough to accommodate a Grommet.
I'd get a Vinyl Hose Fitting to "Mount" in the Grommet.
Add a short length of Hose.
Join 2 into 1 with a "Y" Fitting.
Add a Filter and hide the plumbing and filter beneath the Tank.

 

Instead of drilling holes in perfectly good carbs just make the block off with a small hole with a tube installed extending into the air filter?

 

That was my FIRST Mod.

My thought was to run the Hoses outside the Pod.

Might work.

 

I am in the process of trying to machine a plastic plug to fit inside the horn to run a tube from to the outside of the pod. I may have to drill a small hole in the top of the horn and tap it and use a small set screw to hold it in place. if it works i will try and post pictures of it.

 

Wouldn't it be easier to just run a stock airbox in it's intended configuration? Sounds like a lot of work just to look cool.

 

pods and jets are cheaper than buying the stock airbox, mine was cracked when i got the bike and the boots where all terribly rotted. besides, i can now store tools,drinks, and other items where my airbox was formerly located.

 

I'm with zookie. If my airbox gets any worse, I will try to tackle running pods before I shell out $200+ for a new airbox and new rubber hoses.

 

Well, I looked at my carbs and it seems I won't be able to drill and tap because of the bracket that connects the 4 carbs together. It looks in the photo rick, that the mikunis have more space between that bracket and the flat part that the pod secures to.

I might just fabricate some new velocity stacks that would have a hole to run the line out of like genros illustration. That way you don't have to put a hole in the pod or the factory rubbers. And then connect them to a filter via some type of manifold.

However attatchment to the oriface in the carb is still needed to devise.