SIMPLE MOD MAY SOLVE POD TUNING HARDSHIPS!

You do realize that doing this mod with a home made custom exhaust means the results will not be valid for those with standard exhausts?

 

2000 miles of my testing was before I did the custom exhaust. That is how I realized that the exhaust itself causes a problem too, on the design they used. it’s the reinvents of the pods not the overall system. I’m trying to get the pods to work correctly. Yes I do realize that with the custom exhaust i have to go up in jets but that is a given with any engine mod to an older bike.

What I am trying to do is allow the pods to breathe and not cause too much interference/turbulence with the upper kidney opening.

I have been looking at the design of the carburetors and going over air flow. After spending about 4-5 hours on this problem with the air flow what each part does. I have decided that I will be making a rig that hooks a vacuum on a dimmer switch to allow changes to RPM and air velocity. This will allow me to test the carburetors and how they pull air across with the stock air box and Pods set up. This will allow for further trouble shooting of the pod setup.

 

Where to get 140 jets ?? Your bike takes 110 - -

You're going +30 ?? on jet size. . .(thirty! 8O )

RickCoMatic has posted a handy-dandy drill bit table,
you just drill them out yourself if you can't find them.

 

yes i have a custom 1.5 exhuast with no mufflers and pods. I have 128 in there now and running lean after exhuast mods. all i had to do to fix with stock exhuast was put 130 and would have been great

 

Its just that this was meant to be (as per the title and the original theory) a simple mod so people could just do the mod when they put on pods.

Can you fit pods and do the mod ride away all good with no tuning hardships? Y/N

 

don't know yet.... Put with out going up in jet size no because you are increasing the air into the engine so you have to increase the fuel there is no way around that

 

The initiall Test was done with 1 Carb hooked-up to the Hose of a Shop-vac.

The idea of a dimmer switch sounds like a good idea. You should be able to match real Intake Vacuum rather than W-O-T conditions.

 

Ok so this is what i have done to help fix the turbulance problem. I put a small camera at the end of my carb. This allowed me to look into the carb as they ran. i ran the bike and noticed that the fuel delivery from the orfis tube looked like it spottered more than anything. Wasn't a smooth flow. i put a 2 inch piece of tape over the filter on one side. One this restricted the air two it it allow an area that doesn't pull air in and seems to have a better draw from the orfis/neddle. will keep testing but u may be adding a plate to the inside to help calm down the intake turbulance

 

I know someone on here added restrictor tubes inside the pods and they claimed it helped. Makes some sense.

 

To have the FUEL exit the MAIN NOZZLE (Emulsion Tube) there needs to be:
1) A Lower PRESSURE at the Top of the TUBE
2) MAIN AIR present surrounding the Tube to get drawn-up bringing MAIN JET FUEL with it.

Rivulets of FUEL getting draw-up into the Intake Stream do not supply sufficient power.

To combat the conditions which cause the MAIN JET supplied FUEL to Rivulet you have to solve two problems.
a) Shape and Speed of the moving column of AIR above the Orifice.
b) Supplying AIR to be drawn-out the Orifice.

These two circumstances require:
• A "Shaping device" -- i.e. Velocity Stack
• Insuring that there is a sufficient MAIN AIR Supply.
>> Atmosphere
>> Larger Ports in the Nozzle
>> Larger Main AIR Jet

*** Possibly modifying the Diaphragm Piston Orifice and Spring Resistance to allow the Diaphragm to LIFT earlier and faster when Manifold Vacuum is present.

 

What a saga! I was practically biting my nails for the ending! Reading it through though makes me wonder if I should just get a new air box (my 700 didn't come with one and currently has pods)...Alas, it doesn't hardly run at all

I do have a general question about carbs (hope it's ok to post it here):

The previous owner of my bike said that on all 4 carbs, he was screwing in the jets and the tubes which the jets set into "broke" loose and would spin. He suggested that I seal the perimeter of the tubes against the carb bodies. He thought there was a vacuum leak at that contact point and is part of the reason why it won't stay running.

Is it normal for them to spin and if not, any thoughts on the best approach to remedy it?


(Please excuse the lack of technical names in my description...I tried looking them up in my service manual; but until I pull the rack, I won't know which exact tubes and jets he was referring to...He seemed to think it was abnormal nonetheless.)

Anyhow, great work everybody!!! An amazing thread for sure!

 

Rick's previous post gives you the terms - "MAIN NOZZLE (Emulsion Tube)" and your Main jet is screwed into that. You could tighten this by placing some tape on a Phillips screwdriver, and then apply some pressure to the "NOZZLE" with one hand, while tightening the jet. Don't get it too tight !! (the tape keeps the Phillips from gouging the brass.)

Epic thread indeed !!

 

Are you kidding me you have not figured this out yet

 

Shhh... there's a reason for that...

Ejpt your question about the emulsion tubes will answer itself once you take the carbs apart. And from the sound of things you're already further along knowledge-wise, than your PO.

 

Thanks bigfitz52. The PO seemed like he knew quite a bit about motorcycles in general (he actually imparted a good deal of knowledge to me), however whereas he ran outta' steam on the project, I have an abundance...Maybe I'm a blind fool; but I'm having fun so far!

 

"Seemed like" being the operative phrase. He did rip the airbox out and pull the front brakes off, after all.

You might want to fact-check any of that "imparted knowledge" before trusting it.

 

Don't risk applying sealant too the Emulsion Tubes. You risk clogging the Air Orifices.

Use an Artists Wooden Handled Paint Brush to "Set" the E-Tube.
Fit the Tube on the end of the Brush and guide it into place.

Apply pressure to the Brush Handle to prevent the Hitachi Emulsion Tube from spinning while tightening the Main Jet.

Mikuni's are Slotted and Keyed.

 

Thanks for the tips guys...Sorry...Wasn't trying to hijack the thread...I'll wait patiently along with everyone else for the riveting climax to this saga!

 

I'm rather new to bikes so forgive me if my understanding is off; but (correct me if I'm wrong) that a problem with pod filters is the fact that:

Each carb will yield different air pressure based on its physical position on the bike and CV carbs need the air pressure to be the same between all the carbs.

It has been said that staggered velocity stacks will help with this (by making the air pressure more-or-less equal on each carb I presume).

It seems like this approach would only be an approximate equalization and in a stiff cross-breeze or perhaps when in a sharp fast turn could in effect greatly mess-up that approximate equalization.

Why not have a single slim air box between the carburetors and the pods which would bridge the carb's airspace together and create equalized pressure between all carbs? This seems simpler than trying to fine-tune the staggered velocity stack lengths to compensate for the differences in air pressure.

The box could be fitted with adjustable baffles so that each pod's "contribution" to the air pressure could be adjusted...Maybe even a baffle for each carb too.

I don't know if this is an absurd proposition. I'm just trying to understand carb dynamics.

 

Ejpt - no, the problem is not that diff carbs see diff pressure. They don't "suck air away" from each other, and the airflow around the engine isn't that big a deal; if airflow was the problem, the bike would run fine at idle or on a dyno after mounting pods, and only have trouble on the road.

The problem is that all the carbs see different airflow (usually more at high rpm, less at low & mid rpm) relative to RPM than what they were initially set up for. Although, if Rick is right, it looks like the air flow pathway relative to specific parts of a carb may also be an issue.

 

Thanks for clearing that up sebwiers. I'm kinda' new to all this and appreciate the info.

 

I am Wondering what Rick was using to make the SMOKE when he was testing these carbs I Think I can guess what it was

 

Designed for, not just set up for. It's not so much that it's "different" airflow (it is) it's the "shape" and pressure (or lack thereof) of that now unrestricted supply of air. We have had a couple of members that have had great success by installing their pods on the ends of the original rubber airbox-to-carb boots (which are in fact, cleverly disguised velocity stacks.)

Look at the design of the original airbox. The four stacks all go into a wide, common chamber. The air filter itself is in a different section of the box; with the size of the opening between the two regulating the volume of air fed into the "intake" chamber.

The airbox regulates the volume of available air. The BOOTS act as velocity stacks so that the airflow into the carbs isn't turbulent.

 

Reading this thread makes me absolutely positive that I will never ever be interested in changing either of my bikes to pods.

The time and effort that has been spent on the pods in this thread is more than I have spent getting my 650 from no start and die on throttle to running like a scalded dog.

Never have I wished either of my bikes had more power.

For those that want to mess with pods more power to you. Pun intended.

 

Amen.

And 9 times out of 10, it's done for looks without any thought being given to what the effect on the motor will be. The rampant willingness to sacrifice real performance in the pursuit of "cool" is something that simply escapes me.

But then I never have been all that big on "form" over "function."

 

The first thing a new owner should do before ripping-out the Airbox and fitting individual Pods on the Engine; is spend the time doing a Full Monte' STOCK Tune-up.

Adjust the valves.
Thoroughly clean the Carbs and Polish the Bores.
Complete all the processes to place the Carbs ready for Tuning.
Bench Sync, Colortune and Vacuum Sync the Carbs to the highest level of Fine Tuning possible.

Know how well the Bike will perform before initiating modifications to the Intake.
Experience how well the Plant can deliver exciting performance throughout the whole power-band and cruise all-day long at 6-Grand on-the-tach, as smooth as a baby's butt, making you wish there was another gear or two to shift too.

 

I couldn't agree more.

But isn't this your thread to begin with?

 

I just want the New Members to understand, ... that while I DO NOT recommend installing AIR PODS, ... I am involved in trying to find a solution that will aid in overcoming the problems inherent when they are substituted for the Airbox.

 

Again, I couldn't agree more.

Which is why I don't understand why everyone keeps ignoring the obvious. A large part of the solution is right before our eyes: the original carb to airbox boots are velocity stacks.

We have one or two members that have enjoyed great success with their "pod-modded" bike by simply using the stock airbox boots between the pods and the carbs.

I'm betting that velocity stacks, which help to shape, direct and speed up airflow, are a lot more important to the equation than we've realized, mostly because the stock boots just look like rubber tubes.

Anybody with a stock bike IS running velocity stacks; it's just not apparent.

 

+1 on what Fitz said. A good look at it was the pictures that ManBot put up on another thread showing how the boots mate to the opening in the carb intake. Definately shows that they have an integral part in the intake process.

What would be interesting to see would be for someone with carb that has been cut in half to put a piece of clear plexiglass or something over it and run smoke through the carb with the intake boot and without to see the turbulence effect first hand. Just a thought.

 

So, this thread is a year old (just shy), and I still do not know if anyone has tried the RickCoMatic fix and run their bike for a few thousand miles. Are there any road results out there?

 

Alright, excuse me if this has alteady been tested, but what about drilling into the top hat of the carb? Rather than from the carb body?

 

The Top Hat on the Carb seals the Diaphragm Chamber and allows the Vacuum to form raising the Piston.

What is needed is a supply of Atmosphere BELOW the Diaphragm.

To feed MAIN Air.
To allow the Diaphragm to collapse.

The shortcut to achieving this scenario is:

Cap the Kidney Shaped Atmosphere Vent on the face of the Intake Horn.
DRILL a 1/4 Inch Hole in the Intake Horn, ... behind the Vent to the side of the Band where the Rubber Boot gets affixed.

Stick a Quarter Inch Grommet in the Hole.
Attach a miniature filter.
Increase the Size of the MAIN AIR JET
Experiment with Emulsion Tubes drilled with extra Air Venting Holes
-OR-
Drill the existing Holes ... Incrementally larger from bottom to top
-OR-

BOTH!

 

As a temporary test, could a baffle be placed over the vent hole? A small piece of aluminum can, folded and seated under the pod lip with a gap at the face of the vent, should reduce the extremes of pressure fluctuation and maybe give a clue to what's going on.

 

The Atmosphere Port on the Face of the Horn does need to be Sealed.
A Plastic cut-out epoxied in place should suffice.
Or, a Plug fabricated from a Gum Eraser and secured with Contact Cement would be equally as effective.

Each Body needs an Aux Vent.
Drilled to the rear of the Atmosphere Vent to provide a source of Atmosphere to feed the Pilot and Main Air Jets plus allow the Diaphragm to collapse when there is a Pressure Varient.

Initially, there was an uproar from those concerned about ruining the Carbs with the Aux Atmosphere Vent getting drilled through the Carb Body.

Any sized Hole drilled in the Carb can be easily PLUGGED with any of a wide variety of Rubber Stoppers and Plugs available in the aftermarket.

After the Atmosphere question is resolved; the SIPHONING VOLUME of Main Jet Supplied Fuel needs to be addressed.

The MAIN AIR Jet would need to be enlarged or simply removed.
The MAIN NOZZLES (a.k.a. Emulsion Tubes) also need to be altered to allow MORE Main Jet Fuel to be Siphoned-up into the Intake Stream.

Additional Holes of the same size drilled between each of the existing holes.
•Or•
Enlarging the AIR Bleeding Holes --> Incrementally <-- to regulate the amount of Fuel getting Siphoned-up into the Intake Stream to remain close to the optimum stoichiometric (1) ratio to assure maximum performance throughout the Power Curve.

Finding the solution may also involve:
Different Sized Diaphragm Piston Needle Valves
Shimming
Altering the Single Hole at the Bottom of the Diaphragm Piston.
Possibly adding an additional hole in the bottom of the Piston to lower the pressure in the Diaphragm Cavity making the Needle rise more quickly.

(1) http://www.engineeringtoolbox.com/stoic ... d_399.html

 

It may sound a bit too simple but a way to make that mod reversible and to repeat the experiment numbers of times could be to shape rubber pieces to fit snug in the kidney shape tunnels.

In a try-and-error process, one could drill each rubber plug with different bit sizes prior to push them in place, to allow different amounts of air to go through those kidney passages and see if a specific diameter is the best.

Then it might be useless to drill the top of the carb intakes. The carb rack used for experiments wouldn't get messed up.

Or a different way to experiment could be to shim a jet with two rubber pieces in the kidney passages, and experiment with different jet sizes...

Just my two cents.

 

The "Bypass" theory involves SEALING the Kidney Shaped Atmosphere Orifice, NOT regulating its size.

We need to PREVENT air from flowing across that Orifice.
When Air flows ACROSS the Orifice, pressure within the Cavity behind the Vent is LOWERED.

Sealing the Opening on the face of the Horn and providing Positive Atmosphere to the "Below-the-Diaphragm-Rubber" Cavity is necessary for the Bypass to help eliminate the Lean Condition of naked PODS.

 

All right, so why not use properly shaped rubber plugs to block these orifices? They would be more easily removed than metal solder if one wants to reverse the mod.

 

Ok, I am just curious about something in this theory. I noticed while cleaning the carbs, that when air from a blowgun is passed over the kidney shaped holes, that the pistons slam open. having the throttle open or closed made no difference on whether air passed over the orifices raised the pistions. So my question is how will the pistions rise with this port plugged??

 

The Atmosphere Vent Bypass is still on the drawing board.

My initial concept involved drilling and plumbing.

Eventually, we Plugged the Atmosphere Vent with a Plug that had an integrated External Air Vent running through the Pod.

::::: Integrated Vent Tube Through Pod :::::


Rather than hassle with running a Vent Tube through the Pod, ... it would be easier to:
• Drill a Hole in the Carb Body to the Front of the Horn
• Install a Grommet
• Add a Plug-in Filter.

The Bypass only solves the problem of Negative Atmosphere at the Vent Opening that causes a lowering of pressure in the Cavity below the Diaphragm Rubber.
> Causing the Diaphragm to not easily collapse.
> Starving the Pilot and Main AIR Jets contributing to the LEAN Condition.

We still need the MAIN JET Supplied Fuel Siphoned-up the Nozzle AND Atomized as it enters the Intake Stream.

>> Additional Holes in the Nozzle (Emulsion Tube)?
>> Incrementally enlarged Holes in the Nozzle?
>> Larger or eliminating Main AIR Jet?
>> Larger or additional Hole in the Bottom of the Diaphragm Piston?

 

:lol: ok, then why on earth just plug one hole to create another. All this seems to accomplish is moving where the carbs draws in the atmospheric air. Also creating a need to make a filter on this new opening. When I first started following this thread, I was really intrigued. But stumbling on the effects of air on the kidney opening myself on accident, got me thinking a bit more anylitical about this whole topic. So, it seems to me that this kidney shaped hole is just "there" to provide filtered atmospheric air a place to enter the carb. So when the butterfly valve is opened, that pressure differtial makes air move in thru the kidney hole, and lift the piston. So it seems that this is putting the cart before the horse, so to speak,since what is not being addressed is the increased volume of air supplied by the pods instead of the balanced volume of air supplied by the stock filter box.

 

"since what is not being addressed is the increased volume of air supplied by the pods instead of the balanced volume of air supplied by the stock filter box."

We fought about this back in 2006.
We know there's more air!
The problem is the AIR is NOT Shaped or Accelerated.

We acknowledge the Volume of Air is increased.
We're trying to do other things than just ... "Re-jetting"

Re-jetting, ... alone ... won't solve the problem.

 

The KIDNEY-Shaped Hole IS the Atmosphere Vent.

When the Rubber Boot is affixed to the Carbs Intake Horn a captive volume of AIR is moving Toward (an AT) the Vent.
A POSITIVE Atmosphere is present, there.

When a POD is affixed.
Intake Air cascaded into the Intake Horn.
The Intake Air flows OVER and ACROSS the Vent.
The Pressure is REDUCED at the Vent Hole.

This is why Sealing the Vent at the face of the Horn and Providing a Aux Vent elsewhere is necessary.

 

wow I only read the first and last page,one lil bit from me maybe dumb but...I think my GPZ carb may have the aux vents installed stock,? If I am mistaken please excuse my ignorance rick was this proposed solution possibly inspired by another carb design? will follow up and read this whole thread as i am rivoted by the whole drama of it!!!!!hahah

 

what about upgrading carbs instead of doin g all that drilling just replace for a set of say xs1100 carbs ?? what would be a good swap

 

Putting a set of bona fide racing carbs on, from Keihin or Mikuni would make having Air Pods to look at a whole lot easier.

$700 -to- upwards of a grand!

For a cosmetic mod!

Maybe a couple of ticks faster in the quarter-mile, ... but not a whole lot more to gain at top end.

I've heard a few stories about guys who bought Carbs of an early '80 Kaw Police Bike and tried to make them fit a 750 Max and Seca.

I doubt they are a bolt-on substitute.

 

wouldnt xs1100 carbs do the trick ?

 

Members and Visitors,

I probably shouldn't be posting this because of my POD ignorance, but what the hay. Rick, you're suggesting plugging the Atmosphere Ventura, installing a small filter below the diaphram in the carb body right behind the ventura vs plumbing the PODS to compensate for the un-stacked large amount of air moving across the ventura with PODS and modifying the emulsion tube, diaphram piston, main fuel jet, needle and or a combination thereof in order to get the proper air/fuel mixture through each carb body, right? Sounds like a plan, but how would you locate the filters on carb body #2 and #3 without changing the Atmospheric air flow by adding a piece of hose to make the connections in the limited space between the carbs? The process of modifying/testing the main fuel components in order to get the diaphrams to rise and drop providing the proper main fuel flow makes my brain hurt. 8O Then again, how much and what type of fruit do we bare without the work. You are a intelligent man, and although I plan to stay with the stock set-up I hope you and others find a solution to the infamous PODS for the sake of all those members who wish to use them. Lastly, I did state I'm ignorant to PODS so I feel comfortable saying this...Why not ask a company to manufacture a set of PODS say with built in restriction at the Ventura? Yeah, I know...good luck with that one. Okay, everyone can laugh now. :lol: 8O

Gary