SIMPLE MOD MAY SOLVE POD TUNING HARDSHIPS!

The RickCoMatic Auxiliary Air Bypass.
. . . . . . . . . . . . . . . . . . . .

The REAL Problem:

The Pods contribute to a LEAN Condition because a VORTEX forms at the INTAKE Horn LOWERING the Pressure at the Kidney Shaped Atmosphere Vent at the Top of the Intake Horn.

Because the Pressure is LOWERED, ... BOTH --> MAIN AIR Supply and the VOID in the Chamber surrounding the RUBBER DIAPHRAGM are starved for AIR.

This causes:
1) The Piston to NOT Rise as effectively as needed, ... and
2) The MAIN AIR needed to surround the Center Emulsion Tube that's essential for Siphoning the Fuel UP into the Intake Stream ... Plus --> Atomize the MAIN JET SUPPLIED Fuel is far less than required.

Before you attach the Pods, ...
SEAL each of the Kidney Shaped Vent Openings with Kidney Shaped Brass Coverlet silver soldered to make the Vent AIR TIGHT.
(Brass Shim Stock cut to size).

DRILL an Opening on the Carb Body beyond the Soldered Shut Vent.
Using Vac Hose or Tubing, ... Fabricate an Auxiliary Atmosphere Vent.
Connect the 1 & 4 Carb with an AUX VENT Hose (Passage) and place a "T-fitting in the Center with a Hose Vent secured between the Middle Carbs.

Likewise replicate an AUX AIR Passage for 2 & 3.

Having a supply of Atmosphere feeding the VOID beneath the Rubber Diaphragm will allow the Diaphragm to more quickly respond to Manifold Vacuum.
(Alleviating shimming)

The Atmosphere made present will also satisfy the MAIN AIR Jet's need for Atmosphere to be drawn-through the Main Air Jet Passage to the Emulsion Tube alleviating a Major Contribution to the LEAN Condition caused without sufficient AIR present.
(Possibly alleviating Power Band lag due to Mixture issues)

This Modification is:
The RickCoMatic Auxiliary Air Bypass © 01.11.12

(This rough sketch on parts carbs is a visual reference. A precise visual will be made when the Parts Carbs I bought to modify and photograph arrive.)



Have FUN with it!

 

Re: SIMPLE MOD SOLVES TUNING FOR PODS. Easy as 1 - 2 - 3 !!!

So does this sentence indicate that you have not yet actually done this to a set of carbs?

And if that's the case, how do you know it will work? The theory is sound, but until actually tested I don't see how you can pronounce it to be a solution. There may be some other aspect of the situation that you hadn't taken into consideration.

I'd have to see the mod actually done, and tested, before I could call it a true solution.

Right now it's just a good theory.

 

Re: SIMPLE MOD SOLVES TUNING FOR PODS. Easy as 1 - 2 - 3 !!!

No.
I dont have a complete rack of my own to alter.

I ran a test blocking-off the Vent on a set that came in for cleaning.

Using washer fluid and a shop-vac ...
Vent left open showed fluid struggling to exit the E-tube.
Closed-off with a hose protruding from the vent held away from the horn showed a steadier flow of fluid leaving the E-tube and the Piston moved higher with a smoother motion.

I'm sure it would improve some if there was a way to mount the Pod to the Rubber Boot.

Shorty velocity stacks are 90-bucks.
I'm working on fabbed-up stacks, too.
Trying to keep the whole mod under 30-bucks.

 

Re: SIMPLE MOD SOLVES TUNING FOR PODS. Easy as 1 - 2 - 3 !!!

Wow
I tinker with a lot of ideas and have made things that have proven to be something worth promoting, but to promote as a fact an untested idea is scary stuff dude.

 

Re: SIMPLE MOD SOLVES TUNING FOR PODS. Easy as 1 - 2 - 3 !!!

It's innovative.
Easier than swapping jets.
Costs under 8-dollars.
Totally reversible.
A caveman could do it.

Pretend I'm Australian.

 

Re: SIMPLE MOD SOLVES TUNING FOR PODS. Easy as 1 - 2 - 3 !!!

Excuse me? Aren't you advocating soldering shut original passages in the carb; and then DRILLING NEW ONES???

Explain how "totally reversible" applies, please.

However, that wasn't the true objection. Both darkfibre and myself have expressed a strong objection to something being trumpeted as a "solution" when in fact, it is as yet UNTESTED.

Honestly Rick? For years I've seen you admonish folks for advising that members perform "irreversible" or "untested" mods on their bikes;

and now you're presenting this UNTESTED THEORY as a "solution."

I'm sorry, my friend; as of now this is NOT a "solution." It's an UNTESTED theory. I'm really surprised that you, of all people, would present it as "here, this will work" when all you have is an experiment with a shop vac, windshield washer fluid, and some tubing (no drilling.) That's a "lab experiment" not a real-world test. Not by a long shot.

Until this has been done to a rack of carbs; installed on a bike equipped with pods, and tested it simply isn't a proven solution. Just a (granted, good) theory; but a theory nonetheless.

Good thing I'm not Australian.

 

Re: SIMPLE MOD SOLVES TUNING FOR PODS. Easy as 1 - 2 - 3 !!!

You can say the same thing about Jetting.
Re-jetting is mostly guess work.

Say whatever you want about it that will make you happy.
The process alleviates the severe lean condition.

And if your objection against reversibility is that that Shim-stock Brass Coverlets soldered on to the Kidney-shaped Atmosphere Vents would be difficult to remove and a small hole drilled into the Body's not able to be plugged with a rubber grommet renders it irreversible ... you gotta be kidding me!

Go ahead and object to what I have proposed as a solution all you want.
If anyone tries it and doesn't like it, ... send me your Carbs and I will remove the Covers and Plug the small holes, ... for FREE!

There IS one thing I do expect to have said about this discovery when you pass the information on to someone else.

It was a relentless old man named Rick Massey who is the guy that figured it out.

 

Re: SIMPLE MOD SOLVES TUNING FOR PODS. Easy as 1 - 2 - 3 !!!

Massey, if you're that relentless get a used rack, do the mod, and put them on a bike. If you don't want to pull your own airbox, ship them to a member who's struggling with pods, and see if it solves his problem.

Until this has been field tested, you simply cannot call it a solution.

It might be. Prove it. Right now it's only a theory and can't be anything more until... proven.

You're engineer enough to know that. C'mon now.

 

There, ...

I rewrote the Thread Headline.

Removed: Solves.
Added: "May"

 

if someone can solder brass to aluminum they can do anything

 

Re: SIMPLE MOD SOLVES TUNING FOR PODS. Easy as 1 - 2 - 3 !!!

Now I understand properly.


You're taking the piss.

 

I realize the best advice to give someone hoping to have a well tuned bike after he had demolished the air box and installed air pods has been:
"You gotta re-jet"
Everybody says it. That's what you do. Re-jet.
Again, ... and again ... once more ... almost got it. Close, but no cigar.

There are formulas for rejetting written down that are supposed to be precisely what to do depending on how you have accessorized.
Worthless.
There's a mountain of posts and follow-up posts from those who followed the formula ... weren't successful, so, ... the advice starts to become desperate shots-in-the-dark to try this and that or some other thing.

Rejetting really isn't the answer to the problem, though, is it?
Why, ... if a larger jet was installed ... did the problem persist?

Because the Fuel wasn't getting pulled-up-out of the Emulsion Tube with sufficient volume to provide an ideal air-fuel ratio.

If you have just-about had enough of hearing somebody tell you to rejet, washer, shim, bigger this, smaller that, ... keep trying ...

Instead of rejetting again, ... try something new.

Pull the Top Rail.
Drill a small hole in the top of the atmosphere vent just beyond the Air Boot Mounting Band.
Seal the Kidney shaped opening on the front of the horn.
That's it.

Be as spartan or elaborate as you please.
Hoses, fittings, tubing, grommets, threaded fittings and the like can be added to make it look like Star Wars or Formula-1.
(R-C Model Fuel Hose and fittings would be bitchin')
Make sure that the Cover gets on the Vent Opening in a manner that is secure.
I might try Epoxy adhesive with Balsa, ... coated with hardener.
(Something that wont harm anything should it get loose.)

Good luck.
Have fun.
Argue and discuss.
No charge.
Your welcome.

 

If I'm reading this right, rather than sealing off the entire opening and drilling a replacement hole elsewhere, wouldn't merely reducing the size of the opening have the same effect?

As for being able to reverse the procedure, perhaps fashioning a press-in plug made of sufficiently heat-tolerant material?

 

Ya know what? I like this guy! I personally think that we need more people like this that think outside the box. I do have a question though. If I remember correctly the little kidney shaped vent provides atmospheric air to the top of the main jet diaphragm correct? With that said would it not be better to actually plug the kidney shaped port and just modify the diaphragm cover as opposed to drilling a hole in the carb body?

 

The top of the diaphragm is subject to the Venturi that it is, in fact, controlling, thru a small hole at the bottom of the slider-piston. This is low-enough pressure to lift the slider-piston and compress the spring.

The "Kidney" vent vents to the UNDERNEATH surface of the diaphragm, and also supplies air to the main emulsion tube. This air needs to be at "atmospheric" pressure and PODS disrupt the normal inlet airflow, causing there to be "less-of-a-difference" in these critical metering systems.

That's the theory and I'm sticking to it.

 

Dang Rick, pretty tough crowd.....In the past year or so I've read enough of what you've written to have gained a great deal of respect for you ESPECIALLY on these types of carbs and on this particular point, I 100% agree that this solution would work as advertized. I sure didn't expect the reaction you of all people, received. Not really directed at anyone in particular but I think that if I had a "means and methods" issue with another man over anything, I'd direct it directly to him and not air my laundry....but that's just me.

I feel bad for you but know that you're a big boy and won't let it deter your experimentation.

I belong to a Kaw triples forum where all the "forum originals" hands get tossed up in the air whenever someone even suggests a performance mod they haven't already "blessed". They actually believe the hype that they're riding bikes that will wheelie in the first three gears.....because they've never twisted the throttle to the stop to find out that it won't! I found it amusing at first but it's a real problem now and they all hate me because not only have I heavily modified one of my own H2's, but help the youngers guys mod theirs. "how could anyone sane want more power" was actually written to me in a pm....implying that I must have lost my sanity along the way. I assured him that I hadn't, then let him know that possibly a KZ400 would be better suited to someone of his riding ability...and knowledge level....but I'll enjoy my fully ported H2. One of my forum friends is getting the crap kicked out of him now because he's working again on a 3-1 expansion chamber.....yes, none have worked SO FAR but that doesn't mean his revisions WON'T work but you would have thought that he just said Denco pipes are junk from the reactions.....all from people that really don't know if his revised system will work or not.

Of course MY solution for installing pods on my bike, if it were possible(which it isn't) would be to trash the Constantly Vucked carbs and go with a set of slide or flat slides and eliminate the problem altogether

Have I ever mentioned that I hate CV carbs?

All in fun......

jeff

 

Once you start drilling holes your going to need to know what size hole, that's going to be a educated guess. I'll guess 3/8 to 1/2 inch, pretty big, but who knows, it's a guess.
I did see, on the web somewhere, someone try something like this by modifing the pod to not cover that opening but turbulance behind the motor at speed complacted matters
(No spell check on the fone)

 

There's always more than one way to skin a cat.

The Chamber BELOW the Diaphragm NEEDS atmosphere.
The Diaphragm needs to be able to collapse and there needs to be Air to be drawn through the Main AIR Jet to surround the Emulsion Tube aiding the siphon and atomizing of Main Jet Fuel.

Placing a Hose in the Vent, ... then sealing the Vent and running the Hose to a point away from the Strong Flow of Intake Air will do the trick.

Isolate the Vent from a Pressure Reducing Air Flow over it. (Somehow)!
Without the possibility of whatever you do to implement the Mod not winding-up getting loose and getting sucked-in the Cylinder.

I tend to "Over-Engineer".
I want external tubing, fittings and a painted Air Filter with a fake adjustment knob stuck to it, ... to make it look like a Faux Nitros hook-up.

Holes, Foam-rubber squares and Rubber Bands being the Hillbilly-hook-up.

 

I went back and read all the responses to the last few pod debates, and there seems to be one very simple solution. Further, the one or two folks running it report decent to good results.

I'm talking about "isolating" the pod filter and it's little "wad" of turbulence from the carb mouth by using some form of velocity stack; either the airbox-to-carb boots, or hunks of thinwall aluminum tubing.

I have my own theory on this, and I have no intention of trying to test it because I have abolutely no reason to try to run pods on CV carbs.

Theory being this: We already pretty much know that the "finger over the end of the garden hose" effect of a properly engineered intake restriction will increase the velocity of a given volume of fluid (hose)/air (airbox.)

We also have pretty much figured out that there's a "turbulence" issue with pods that drives CV carbs wonky.

Close examination of a carb-to-airbox boot reveals it to not be straight at all; it has a subtle taper inside-- OMG it's a rubber velocity stack.

I think that's the real solution, or at least a major part of it. CV carbs need velocity stacks, so Yamaha cleverly built them into those pesky boots. CV=Constant velocity. We already hammered our "constant" when we removed the carefully restrictive airbox; but we can escape the turbulence issue, straighten out our airflow and regain some velocity with stacks.

PUT THE PODS ON "STACKS" and I'll bet that with some minor re-jetting you'll get back most of what you lost when the airbox went away.

I think streetbrawler750 is onto something: http://www.xjbikes.com/Forums/download/id=8400.html

No drilling required.

 

Funny, the kidney port is subject to the highest vacuum loads with a totally stock airbox and filter arrangement yet the carbs work perfectly from the factory. The highest vacuum will occur just after the narrowest part of the carb throat (near the vena contracta) and will overpower any vacuum created under the diaphragm by the kidney port which is right at the carb bellmouth opening. The top of the diaphragm, subject to the deeper vacuum at or near the carb throat through the piston vent hole, will have more pull than the bottom, and the piston will open.

A piston on the intake stroke will also draw a much deeper vacuum than a shop vac.

I'd think twice before drilling into the body of my obsolete carbs.

 

If I sounded negative on Ricks METHOD, I apologize.
I follow the reasoning and find it sound enough to be worthwhile and needs to be tried.

My comments were negative, but only towards the fact that it was promoted as a 'finite solution' without being tried.

The bench tests prove 100% that the modification will change the carbs operation, and it will be interesting if those changes are of the right % to work.

This is the assumption that the mod hinges on.
In a standard bike this port is open to the air cleaner not atmosphere, changing it may work with pods or it may even overcompensate.

Can someone just try it, please.
Fingers crossed it WILL be the holy grail pod people need.

 

Funny, every other bike site I go to has hundreds of people happily podding away yet the XJ has some deep dark mystery surrounding it's design that totally rules out their usability.


I BLAME YICS!!

 

With what bikes? High-revving four cylinders with CV carbs?

Or is it simply a case of ignorance is bliss on the way to a holed piston?

A stock system means not having to worry about stuff like that if your ducks are in a row. Pod on; I'll keep my airbox. (I even have a spare.)

YICS rocks.

 

This sounds like a very interesting idea I would sure like to try it if I had pods and a spare rack .
We need more ideas like this!

 

Do we need to call in the 'Myth Buster' ?

 

8O

 

Mac, not every site kzrider maybe 50/50 but the carbs those guys use are a little more fiddle friendly than hitachi's

 

You see, ...
I ... don't ... care ... HOW ... you alleviate the Negative Pressure at the Atmosphere Vent.
The ... important ... thing ... is that it gets done.
Because it makes the Piston rise and lets the Gas get sucked-out of the E-Tube.
Mission; accomplished.

The BIG Plus is, ... Now, ... when some poor soul registers and asks what he has to do to get his Bike running right, ... because he hacked-out his Air Box and put-on the nifty Air Pods he sniped off Ebay, ... you'll have something else to say other than:

"You gotta re-jet!"

There was something else that came-up, ... too.
The issue of Soldering Brass to Aluminum.

Stainless Steel, Brass and Copper can be Soldered to Aluminum, ... using Harris Stay-Brite 8.

http://www.harrisproductsgroup.com/en/P ... ite-8.aspx

Special Soldering Flux is needed when soldering Aluminum to Aluminum or Aluminum to Dissimilar Metals.
You need to use "Harris Stay-Clean Aluminum" flux.

http://www.harrisproductsgroup.com/en/P ... x.aspx?p=1

The Following charges have
been billed to your Credit Cards:

* * * * * $0.00
>>Total: $0.00

 

Could get interesting when all that unfiltered air going into the diaphragm port jams the pistons with fine grit.

 

This is not the time to start getting practical, Mac.

 

Fuel and/or air jets almost always be modified (increased in size) due to the increased airflow into the engine with the use of pod filters, otherwise the dreaded lean condition/hole in piston situation. Greater airflow volume requires increased fuel flow, period.

One of the main benefits of pod air filters (beside that they look cool) is that they are typically very low-restriction, compared to the stock paper filter and somewhat restrictive airbox system.

This is why when you even use the stock airbox with a hi-flow air filter (i.e. a K&N) that the increase in airflow typically requires a re-jet. Ditto for even drilling holes in the airbox itself. The intake "port" (opening) in the airbox is probably small enough to act like a "restrictor plate" a far as airflow is concerned.

Air-cooled engines, which typically run much hotter than water-cooled engines, are especially susceptible to over-heating and resultant piston damage (water-cooled X-engines are not, but have a whole different kind of problem with using pod filters).

Recall, these engines were purposely jetted quite a bit lean from the factory (to meet EPA regs) and there's even a TSB from Yamaha telling dealers how to overcome this problem if the customer complains about poor low-to-mid rpm performance. Although engines that run just a little bit lean tend to perform much better at lower rpm's (as opposed to a rich condition), the lean mixture is a devil's trade-off vs. engine longevity and risk.

Remember, the vaporized fuel acts as a combustion chamber COOLANT as well as a source of power. The fuel absorbs quite a bit of the cylinder wall, head, and piston crown heat as part of the overall combustion process.

 

The next clunk test might be your helmet hitting the road. I hear these XJ's really scream, but probably not as loud as the rider does when he closes the throttle and nothing happens.

You're right about jetting up. I put a Uni foam filter in my GS1100 and removed the airbox lid. It opened up a hole in the midrange as wide as the Grand Canyon.

Also, if you are supplying more air to the main jet, you are then running lean, are you not? Sounds like a prime scenario for a re-jet....

 

I LOVE "modded" liter-bikes that haven't been re-tuned to properly compensate for the changes; things like you mentioned (a big hole in the midrange) or a motor that starts splattering and breaking up at 7~8K-- LOVE IT!!!

Because I can EAT them with a clean running stock XJ550R. Peak HP at 10K; it's really cool when you can actually get there. I do with great regularity, that's what the motor was designed for. Makes it happy.

Bring on a GSXRZ11 whatever with a "pipe" and/or pods and nothing else done... breakfast of Classics.

 

I would try ricks method if I had any confidence in my ability to actually do it.

 

i don't know Rick, i think a man would be hard pressed to solder 4 pieces in, air tight, without a very large pain in his butt.
i've tried several times to do stuff like that with not real good results.
why not put a spacer under the hat to seal the top and vent the bottom and leave the carb throat alone

 

ALL that unfiltered air?

For the Diaphragm to collapse there only needs to be atmosphere.
The MAIN AIR JET on the 750 is: Size 80
Size 80
Just about the same size as the zero used to write the figure 80 ⬅ "O"

There is an abundance of Miniature Plugs to fit ANY hole drilled to allow atmosphere to be present in the space beneath the Diaphragm Rubber.

Aparantly, the requirement to Filter the small holes or tubing ends was not an obviously superfluous detail.

OK.
Cookie-cutter Small Discs of 65 PPI Foam Filter Sheet
Apply Contact Cement ---> ALONG THE OUTER EDGES <---
Cover Holes

 

There's so much I'd like to say about your constant negativity, Polock.

I can always count on you to point-out every possible objection to what I present to the others as possible solutions or thought provoking ideas.

The Members PM me and urge me to confront you.
That wouldn't be a proper thing to do.
While I continue to try and be helpful; you carry-on.

God Bless you.
I forgive you.

 

WHAT'D POLOCK DO???

I'm the one who immediately jumped on this as an untested theory vs. a true solution, then darkfibre jumped in, and debate began over the testing regimen used.

Polock has only brought up practical pitfalls, like soldering brass (or anything else) to a carb body, and unlike myself, has actually offered suggestions of alternative methods to accomplish similar results.

Polock's not been the least bit negative on this subject; he's just being his usual contrite, pragmatic self.

I'M the guy that continues to insist that it's an untested theory that opens up a whole new set of concerns that prevent it from being touted as a solution. If you want to personally attack someone, attack me. You're supposed to be the mod, one who keeps this IMpersonal and technical. But so far you've slammed Ozzies and now torn into Mr. P. for no real reason at all. And he's not even Australian.

It's OK Rick; we forgive you.

Now let's keep this TECHNICAL not personal, and continue. It's still just a theory; who's gonna test it?

 

i nominate rickcomatic. in fact i think he should have done it before posting theories

 

Actually, no.

What Rick should have done when he posted this theory was not offered it up as a solution, but a possible solution.

He changed the title of his post.

But to say that he should have tested his theory, which I believe he plans to do, before proffering up the idea to us? That is not true.

He is very passionate about his theory, and as Fitz pointed out, we need to keep this technical, so we can see if it actually does work.

Don't get me wrong, I'm not defending Rick, and I'm not admonishing what he has posted.

What I am defending is the right, and the need, for people to post their theories on here, so that we can come to a solution, for the greater good of the XJ community.

Rick, I actually hope this theory does work. Not that I'll ever put pods on my bike, but it would be nice to be able to point guys to a solution instead of telling them "spend a couple hundred bucks on jets and good luck".

 

May I add that, due to wind buffeting at 90 MPH, the filters or inlets for the tubing need to be located in still-air, which may require (I'm making this up) a garden hose from under the seat with a single filter there, next to the fuse box. 4 smaller hoses split off later, at the carbs. (not too small, I'm guessing 1/4 ID or more)

The air-jet needs to stay in the system, as it's part of the main emulsion system. I agree there would be a constant flow of dust, as the air is used up in the emulsion tube.

Blocking the opening? - I've had JB-Weld stick to carb bodies for years. But if someone was afraid that the Kidney-Cover could pop loose and be injested, it could be safety-wired in place. Just drill a couple really small holes while you're drilling the larger holes.

 

I agree completely. A theory doesn't need to have been tested before someone proposes it; my entire objection all along was the announcement of it as a "for sure solution" rather than "hey, here's an idea-- how about this?"

THEORIES need to be discussed; it's how we realize the aspects we haven't considered. My only point all along has been that you can't say "this WILL work" when you don't know that it will.

But enough of that.

I still think that adding a velocity stack in one form or another between pod and carb throat would eliminate most if not all of the turbulence at the kidney-shaped opening and provide as straight an airflow as when the airbox was still on the other end of the boots.

We've had one member post quite positive results from that simple idea; I do believe that streetbrawler750 is onto something: http://www.xjbikes.com/Forums/download/id=8400.html

 

Gentlemen,

Mac has nailed my quandary -- which is that the kidney port under factory design circumstances (i.e. inside the factory-box's as-designed boot) will see negative pressure --- just not as much negative pressure --- as the carb throat produces at the piston-point in the flow (from which the upper-diaphram draws its vacum through the two holes in the bottom of the diaphram-piston)...

Therefore, Rick, I know you understand this, but still believe filtered atmoshperic pressure will work OK?

Not an indictment or judgement, I just want to ensure I know what you know?

p.s. First, the arrow in the piston should point the other way -- the increased vacume "draws" the air out from atop the diaphram -- als, please note the lowest air pressure is a result of the carb-throat's smooth restriction of air to a point under the piston -- if you look into the end of the air-box-side carb throat you'll see the funnel to the throat around the piston -- this is NOT well shown on the diagram below

 

Hmmm...

Looking at the diagram; I'm not so sure the kidney-shaped port isn't actually more of a relief port to help the vacuum coming through the slide "buoy" the diaphragm/slide assembly. If that's only part of it's function, drilling holes elsewhere might negate that effect making it more difficult for the slide to raise under certain conitions (like WOT) and cause an even leaner condition than what we're trying to cure.

What happens when the slide is up, and the butterflies are suddenly closed? Which way is air flowing through the kidney shaped port in the next few milleseconds as the slide falls? Are we sure it's not a "two-way port" depending on where the slides and butterflies are in relation to each other under any given condition? Throttle position, rpm, etc.?

I think it's part of the "constant" in CV.

I strongly suspect the kidney-shaped port is shaped the way it is and is the size that it is to provide or allow a very carefully metered and directed airflow in either direction to perform its somewhat mysterious job. It's quite possible that simple round holes placed elsewhere would NOT "duplicate" its function effectively, again causing the slide to drawn up less than it should be for the airflow through the carb at any given time; or possibly causing it to "hang" and not return promptly.

That kidney-shaped port is more than just a "hole." Airflow volume and velocity would have to be duplicated with any drilled holes; and location may be more critical than previously considered.

I'm not so sure the airflow produced by the shop vac would have been strong enough to have revealed these possibilities.

 

Crazy thing about the pod with a velocity stack, on a cv carb- A pod kit is mass produced and dyno proven to increse horsepower on the xvs1100. I bought a kit, cuz it was actually cheaper than buying the pieces seperately, and after removing the airbox, you have to put the pod filters on the factory airbox to carb boot, I laughed and shook my head, I had done that well over a year ago to my xj.

 

Nobody seems to want to hear that YOU may have hit upon the closest thing to an actual solution yet.

And no drilling required.

 

Dont forget CV carb theory 101.


The slide does not 'just' rise to let more fuel in, it stays down to keep air velocity high at low engine speeds.

It is a tuned balancing act.

If the slide is all the way up at 5,000rpm full throttle, and the mixture is lean with pods at that point, jets will still need to be changed for high rpm running.

 

Well, I did drill the slides as per the dyno jet kit instructions for my xj- I wish I would have tested before and after but I didn't. I do know for a fact, the day I was tuning, I rode it with the pods and my mid range just climbed, not really accelerated until high in the rpm range, and it was fine after you got the rpms up- I went back to my garage seen the stock rubbers laying on the bench and put them on the pods and went and rode again, it actually pulled through the rpm range. I don't have technical data to support, but I do know when an engine is performing well.

 

You don't need large holes.
The LARGEST Hole that MAIN Air Passes through is a Size 80 Jet.

The Air Holes surrounding the Emulsion Tube are nearly the smallest found anywhere on the bike.

I'm handicapped; as the members who have come-by here to use my tools and have me supervise them doing a project on their bikes will attest.
I'd do it if I could.

This is for somebody with Pods and a bike that ain't running too well to try.

 

I would bet that you could put a pretty substantial wager on the kidney port havving more than one "purpose", being of the special shape that it is........that's a more complicated shape to design and cast/mill than just a round hole or two, and you can be pretty darned sure that the factory didn't go to that trouble and expense just for "looks".

In any case, more airflow = greater need for fuel if the engine is going to see the "ideal" 14.7:1 air-fuel ratio (or, even operate within the required range of ideal ratios). From my understanding, the restriction on these engines is on the intake side; this is why MAC, for instance, claims (and user experience seems to verify) that you can add their fancy "scavenging" exhaust system withOUT having to re-jet the carbs.........and that's because whatever additional airflow capability thru the exhaust system doesn't make a difference if the stock intake system is still acting as a system "plug". It's also why the general consensus (for however worthy that may be) is that any change to the intake system that increases airflow....EVEN WITH A STOCK EXHAUST SYSTEM....typically requires re-jetting to increase fuel flow to match the now-increased airflow.

Theories are great, but without a deeper understanding of the functional design parameters of all the different parts of the entire system, then it's pretty much just fanciful guesswork. Who knows a fluid dynamics pro with specific experience with carbs? They could tell you in a heartbeat, I presume, how and why all the different parts of a carb are designed as they are, not only in and of themselves, but as part of a system that interacts with all other parts of that system. AND THAT IS THEY KEY.

Remove Saturn from the solar "system" (or heck, even remove the Moon), and sure, you'll still end up with a solar system of some kind, but it'll be a completely different system, one which may not have even supported (or allowed) life on Earth, such is the delicate balances that many systems (great and small) achieve.

Think of all the interesting CV carb discussions that would never have happened if the Earth was able to wobble on its axis by just a few degrees more (without the stabilizing effect of a rather large moon).

Honeywell Corp., back when it was run by engineering types, used to have as their advertising slogan "The system IS the solution." Truer words have rarely ever been spoken.......