For Pod Guys & PVC Manifold Guys ONLY !! By: Rick Massey

Life's a Bitch getting that Bike to run right, ... ain't it?

If only somebody would come-along with something really NEW to try.
OK. Boys.
After I lay this out ... discuss it and continue further experimentation. I think I found a way to get you boys over -the-hump.

RickCoMatic World Headquarters
WTF -- Hook it up and Try Dept.
1- Pod
1- Mikuni
1- Hitachi
1- Gal Washer Fluid
1 -Shop Vac

After two days of experimentation I have come to the conclusion that the Problem of the "Persistent Lean Condition" can be overcome.

Mikuni's:

The Mikuni's Main AIR Jet is at the Rear of the Carbs Intake Horn.
Without isolation or using a Velocity Stack -- The INTAKE AIR Flow REDUCES pressure at the MAIN AIR JET.
Instead of AIR collecting at the Horn Opening and allowing some AIR to Enter the Main AIR Jet ... Pressure is Reduced at the Main AIR Jet Opening ... starving the Main AIR from entering the Jet, surrounding the Emulsion Tube and being used to Draw-up and Atomize Main FUEL Jet Supply.

Solution:

Remove Main AIR Jet.
Affix an Auxiliary Main Air INLET Hose which gets VENTED to the Atmosphere by running the Hose from the Main AIR Jet Inlet through the POD or PVC Manifold to a convenient spot not affected by INTAKE.

A Main AIR Jet Supply Auxiliary Intake Manifold Bypass.
Bingo!
We have a Bingo!

You can smell it, ... huh?
You can feel it happening, ...
Your re-jetting days might be over.
This ain't going to make me run-out and buy a set of Pods or Start fabricating a PVC Manifold.

Buy it gives you guys something to do this Summer that might make it fun to quit Tuning and start riding.

Hitachi:

You have to VENT and SEAL the AIR Inlet above the Intake Horn.
Creating an Aux Atmosphere Inlet
I used wet Kleenex.

I hooked-up a Float Height Tube and watched it work!

 

During testing, today, the Hose worked itself free from the Air Jet.

I'm contemplating using a Press-fit Nylon Hose Union.

But, just to keep the Hose from being pulled-out from the Air Jet, ... I "Painted" the end that slips into the Air Jet with Nail Polish and then "Coated" the whole end with Nail Polish and it stays-put!

 

Just to clarify for my understanding; on the Hitachi I can stuff the main air jet with a kleenex (or something non-porous) and call it done?

 

i *think* what rick is getting at, is the oblong shaped openings at the tops of all the carb throats pictured here:


need to be restricted if pods are installed.

the reasoning being that this oblong hole connects to the top portion of the carb, below the diaphragm.

with a stock airbox set up, the air pressure at this hole drops due to the vacuum of the engine, but pods flow so well that the air pressure never drops, so there's more air available here. (more air for the air jets to lean out your mix that is).

if this is all correct, then i think it would also mean that the diaphragm and piston also goes higher at any given RPM with pods than with a stock air box. which a) acts like you shimmed your needle, but b)also lets more air flow through the carb.

the air jet situation should be fixable with smaller jets. the piston situation, i think would be fixable by partially blocking off that oblong opening.

 

I dont have pods but... can't you just stuff extra air filter foam
inside the filters??
It seems that if too much air it the issue-then just reduce it at the
source. As long as your very careful to make the new foam pieces
fairly the same, you coulld then just tweek them at the pilots.
You can even try diff density foam untill you achive the correct air flow.

 

rick i know what your talking about but alout of people do not that are not carb savy. would be nice if you could show a picture of the hose installed in the back of the carb

 

The Kleenex is what I used to conduct an experiment.

I don't know what I would use to provide Atmosphere to the back of Hitachi.

I think I would experiment with a Piece of Vinyl Hose ... heat the end and see if it would fit the Atmosphere Port and stay-put.
Then, use Caulk or something non-permanent to fill any gap.

The idea is for YOU Pod guys to take the ball and run with it.

 

Re: For Pod Guys & PVC Manifold Guys ONLY !! By: Rick Masse

:wink:

 

I'll roll with it, as soon as I can understand what needs to be done in the first place.

So.... that oblong hole needs to be obstructed... or vented? Or both (how the hell is that possible?) Is Skeeter correct in helping to explain this?

A picture says a thousand words.

 

The Top Oblong Air Vent above the Main Intake Horn needs to be "Vented" ... outside the Pod.
The orifice needs to be able to "Breathe" ... and my theory is that the Unrestricted Flow of rapidly-moving Intake Air CAUSES a DECREASE in Air Pressure upon that Vent.

Therefore, ... Air which is supposed to enter the Passage and supply the Main AIR Jet with Air to be drawn-up through the Emulsion Tube to INCREASE the FLOW of Main FUEL and Atomize the Main Fuel Supply does not get supplied.

 

very interesting...

 

Awesome, exactly what I wanted to see. I'll do my own tests and report back.

 

I've been thinking the same thing. I see people forking out $130 for dynojet. Why not adjust the airflow between the carbs and the pod? I'm planning on running a pvc intake with one pod, I was thinking of just reducing air flow to each carb with reducers or foam.

 

Giving the Main AIR Jets a shot at Air NOT moving AWAY from their Inlets allows the Intake Air Stream passing over the top of the Emulsion Tube to cause a Reduced Pressure at the Opening and HAVE some Main AIR >>Present<< surrounding the Emulsion Tube to be drawn through the Emulsion Tubes Ports and facilitate BOTH Increasing Main Jet Flow and Atomizing the Increased Flow, ...

Increasing the Main Jet Supply
Atomizing the Main Jet Flow ... while ...

helping to solve the problem of Pods causing a LEAN Condition that has been an insurmountable dilemma and the cause of thousands of man-hours of experimentation about what to do about the extraordinarily Lean Condition ...

Until the middle of last week, when an ailing old man from Billerica, Massachusetts found what might be the solution.

But, I ain't ordering no Pods nor fixin' to yank-out my airbox just yet!

 

Rick:
Not wanting to beat a dead horse, but could you show a diagram or picture of how to do the Mikuni carbs please? I am mechanically inclined, but instruction stupid. This is an awesome fix and I would love to try it but this old fella needs better instructions! Thanks buddy for all your hard work and outstanding knowledge! I'm about to buy those pods....maybe.

 

Re: For Pod Guys & PVC Manifold Guys ONLY !! By: Rick Masse

This sure sounds like a good theory Rick. I have been running pods all of last year and new ones this year. My experience with them has been a little different than most I guess. The bike does run lean but not burnt pistons lean. I'll let some of the other pod guys that are having the very lean running conditions test the theory out. I think that the placement of the open ends of the tubes is going to be very important though and the length of the tubes. If this does help the super lean burning piston conditions than I have another idea that may be a better fix I would like to know what you think about it.
-drill a 1/4" hole between the carb body and the filter mounting ring to open the main air vent to the outside air.
-plug off the main air vent inside the filter so you are no longer using the factory supplied vent location
-take a 3/8" x 1/2" piece of scotch pad and glue it over the hole to act as a filter for the new main vent so you don't get dirt sucked into the top of your carb.

WARNING PLEASE DON'T TAKE AND DRILL HOLES IN YOUER CARBS UNTIL WE FIND OUT IF THE TUBES ACTUALY CHANGE ANYTHING.

Well that's my idea on the hole main air vent thing

 

My Theory was Posted to allow Pod-Guys to have an avenue of Experimentation which might drastically affect Intake Mixtures.

If you have Carbs that you use for experiments ... Drill, Baby, Drill.

But, MY design allows you too go back to where you were before making the Mod.
IF REAL WORLD TESTING concludes that the Bike runs better and the Lean Conditions are resolved. I might consider alterations more permanent.

I'm not blessing experimentation that could be a costly error.

I understand what you propose.
It's possible.
Try it if you want to.

 

From what I've read on this site, the main problem with pods is the turbulence of the air entering. It is possible to re jet for any amount of air, BUT the stream of air does not raise the vaccuum slide efficiently inside the carburator. I experimented with changing the way the pod hooks to the carburator by removing the pods' rubber and installing the factory air box to carb rubber velocity stack. Instant mid range recovery, and also increased top end performance. Problem solved, if you ask me.

 

This is an interesting thread, I know it died a month or so ago, but I was just wondering if there's any updates as to how these experiments have gone because I'm about to get some pods.

First, since I've not fgot any pods at the moment, I have no idea if this is even possible. But if free flowing air is a problem with pods, causing the lean condition would it be possible to restrict the air flow.. Perhaps putting a sock in the pod for example? I know it's a simple fix, and there's probably a logical reason why it won't work, but I was wondering...

Also, is the extra lean condition cured by putting much larger jets in? Dynojet stage 3 comes to mind.. I'm happy to spend a little cash on that if it cures the problem, because logically, if you're putting 10% more air/fuel mix into the cylinders at the magic mix, you should get 10% more power..

 

I am sticking with my guns on the velocity stacked pod, I have put quite a few miles on since my last post and I am totally sold. The pod introduces turbulence, and that a stream of air is needed to raise the slide, the stock rubbers provided the stream that the pod rubber did not. And more air, and more fuel, does equal more power, within reason.

 

pods don't give the motor more air. each cylinder on our bikes displaces 187 and a half CC's. period.
Pods eliminate pumping losses. The motor doesn't have to waste HP sucking in it's next charge. Had a milkshake lately? too small a straw can make it hard work, especially when you hit a strawberry but if the bugs get that big I'm pulling over.
And while I'm making up analogies... Been in building with old plumbing? ringing pipes. Water hammer. That's where velocity stacks (especially with YICS) come into the picture. The intake valve opens, the piston goes down, drawing in air through the carb bodies and intake. Air this air gets moving and doesn't want to stop just because some silly intake valve has decided to slam shut in front of it. When you shut of the faucet in that old house all the moving water slams together like a freeway pile up accident, pushes outward on the walls of the pipe and the pipe rings like it was hit with a hammer. Water hammer. In out heads the moving air puffs through the YICS passages and adds to and disturbs the in rushing charge of another cylinder. Better atomizing fuel and indeed providing a minuscule amount of "boost" (though with the sizes of passages involve this IS truly negligible)
With your stacks on that "air hammer" gets a better run at it when doing all this.

swissjon, reintroducing pumping loss by re-restricting airflow after having derestricted it with pods would make them a purely cosmetic modification. You'd be gettin' into H-D territory there.

 

I sold the Carbs I was using to do the experiment.

A Velocity Stacked Pod will place Air on the Surfaces of the Vents and provide a constant supply of Air at the Vent for the Main AIR Supply.

Pods don't.

Take an old Carb and hook-up the hose from a Shop Vac to the Intake Neck.
Fire-up the Vacuum.

Blow Cigar smoke at the back of the Carb.
It's not long before there is a Vortex at the back-side of the Carb.
Air that should be entering the Vent is sucked-into the Carb.

That means there is diminished pressure at the Vent.
Insufficient Air to the Main AIR Jet.
The Main AIR Jet NEEDS that Air to get Fuel out of the Emulsion Tube in a manner that is equaling the demand and atomizing that which exits the tube.

 

Ok thanks, so to remove all the technical speak from this, so us idiots can understand.

Putting a sock in it WOULD work but won't give any other benifit from having pods. (I knew it wouldn't improve engine performance, I was just interested if this would help at all if I decided to modify my bike in a way that made a normal airbox impractical)

Putting in a bigger jet set does help but doesn't resolve all of the issues involved with the additional air flow.
Putting in these funny pipes Rick designed helps with that. Other people have found that putting on the original rubbers onto the pods also helps.

Does this about cover it? What have I missed?

 

The factors that needs to be overcome are:
A generally "Too Lean" Mixture.

Removing the "Flat Spot" approaching Wide Open Throttle.

After reviewing the Smoke Test and watching Washer Fluid exit the Top of the Emulsion Tube ... I'm thinking that someone will soon find a revised formula of "Re-Jetting" that will allow the Bike to run quite well on Pods.

Main AIR Supply will be an important consideration.
IF ... The Main AIR Passages are large enough and will allow the necessary amount of AIR to surround the Emulsion Tube and be drawn through --> Progressively Enlarged Emulsion Tube Ports, ... a Larger supply of AIR ... will bring-up more --> sufficiently ATOMIZED Fuel ... that will not be wasted by entering the Combustion Chamber in a Large Droplet State that won't provide the efficient BURN needed to make power in the higher rpm's.

IF ... The Main AIR Supply is INCREASED
The Emulsion Tubes Drilled for Progressively More Air.
The FUEL entering the Intake Stream will INCREASE.
The Lean Condition lessened.
Possibly making Tuning less of a challenge.

 

Re: For Pod Guys & PVC Manifold Guys ONLY !! By: Rick Masse

Thanks Rick! I can't believe it but I actually got it right away. 8)
Myself I would never convert to pods, but if I do buy a bike with no airbox, I will try your fix.
Bill

 

swissjon, removing the airbox is, in itself a VERY practical mod. Once complete you can stow a 2liter bottle of soda pop under the seat with room to spare. For a while I kept a quart of oil and a can of ether in there until I fixed my valve cover gasket and enrichment circuit.

Other than that it makes for a long road to tuned.

I'm in the "don't mess with the precision engineering" camp except that mine was cracked such that it wouldn't hold filters properly and putting a new box in meant dropping the motor out of it's mounts. Also the bike came to me with aftermarket exhaust and needed proper jet tuning for that anyway. I'm also in the "lazy" and "cheap" camps. So I've been fiddling with pods ever since.

Oh and don't forget to hook up a crank breather filter or at very least a J-tube (legality and opinions of safety vary on the latter, not opinions of how safe it is, opinions of how safe you want to be) If you ever plan to take it on a track neither of these mods will let you on.

 

I used the original rubber velocity stacks with foam inserts and it bumped my flat spot to around 7k RPM (the flat spot used to be at around 6k with pods).

Because my stacks have foam and a piece of PVC piping in them (to hold the foam in place as an assembly) I'm thinking that some of the air flow is disrupted. I'm going to make some better filters and give it another go.

 

this is very interesting

i want pods too, only for the looks, would i need to rejet anyway because of the pods? in previous threads on the issue reads some guys havent rejetted and some guys have had to?

streetbrawler i like your idea, can you tell me more about it with a picture maybe? or has anyone else tried that?


mestnii post results!

 

I will work on a picture, and write up of the mod, my internet is down at home so I have to get on here at breaks at work. I have no flat spots with my bike, I twist the throttle it pulls even from a dead stop and starts screaming at 6 grand, pulls all the way through till I shift. I usually shift around 8500 cuz I don't want to beat on it too hard.

 

I like Streets idea too looking forward to seeing it as well. lucky for me i still have the parts to try a couple of things if that does not work but with the proven road time its hard to argue.

 

Just to throw it in here, I agree with Streetbrawler. The key is to use the stock velocity stacks. On my race bike Seca 550 I am running stock carbs with a pretty open 4-1 pipe and open stock velocity stacks. I only changed the main jet and shimmed the needle and the carburation is perfect to past redline. I have also done this on a cb350 race bike with CV carbs using the stock velocity stacks and the foam uni-filters. The difference between the stock velocity stack and bare carb body was a 100 main jet with the bare carb and a 135 main jet with the velocity stack. The velocity stack does increase the amount of air introduced into the cylinder as evidenced by the need to increase jet size to maintain the proper air fuel ratio.

Ken

 

i love this. answers and ideas. i was goig to run pods due to space ( modified battery box). after this i am moding my stock air box th fit fith a panel type filter. i will update as soon as get her goin.

 

I will definitely be trying Streets theory (as it seems the easiest and quickest) but Ricks theory seems like another plausible one. When i get my pods i will attempt both.

 

The Custom Air Pod which MIGHT do the trick would look like this:

A Pod with an:
Exterior Filter Element
Interior Velocity Stack
Attaches to Carb Horn with a form-fitting Rubber Boot with a Screened Cut-Out for the Atmosphere Orifice atop the Horn.

The Pod rotates.
Two layers of perforated sheet metal allow the Intake Air to be regulated.

 

just wondering if there was anymore progress.. streetbrawler.. i wouldn't mind trying your idea... just wondering if you got to drawing it out of taking a pic...

 

does anyone have any pics of this i would like to try it

 

Bumping this to the top to see if any progress has been made on this. I was sold on just using the stock airbox........until today, when I had to re-hook my carbs to the airbox, that is! The damned boots kept wanting to slip off the carbs! Really had to crank down on the clamps, all the way, in an effort to keep them from popping loose. Always seemed to happen at the bottom of the carbs, too. You guys have these issues?

 

Ya it worked/works good for me, I haven't changed anything since setting it. I think it works. Let me know if you guys have any luck. I think it changes the mid powerband so it was even, and didn't phase out.

 

Dealing with those Boots is tough.
You can do a few things to make it easier.

Sand the Holes in the AirBox a tiny bit increasing the Inside Diameter.
Sand the widened Holes smooth with 800
Sand the Locating Groove on the Boots a bit wider and then re-sand them with 400 - 800 - 1000 to make them ultra smooth.

Eyeball them.
Get them marked in the right order the fit the Carbs
1+4 have a slight bias.
2+3 are straight.

Microwave them in a Moist towel for 45-seconds
Install the #-3 Boot.
Have the right weapons.

http://www.electricaladvantage.net/pick ... cekit.aspx

Shoot the Locating Groove all-around with Heavy Duty Silicone Spray.

Win the fight.

 

Well, there might be half the problem. I failed to realize that the were essentially location-specific! Thought they ALL had a bias to them. Coulda been why the PO didn't exactly have them shoved on, all the way, too. Good possibility, as I think of it, that maybe the PO even mixed and matched the boots from another donor bike, so that nothing was as it should. Hmmm..... Now the question is, do I investigate, or just leave it be?...............

Either way, thanks for the replies!

 

Sorry to sound stupid but I need some clarification:
Withe the CV carbs am I trying to restrict air to the top oblong hole or the bottom main intake?

My thought would be to restrict the top hole to create a vacum but I want to be sure.

 

That Upper Vent needs to be subject to a condition where it will not have a Great Pressure Differential lowering Air Pressure at its Opening.

Without an Auxiliary Vent Hose and subject to NOT having INTAKE Air "Shaped" at the Horn, ... the INTAKE Air becomes a Turbulent Vortex. Air speeding into the Intake becomes cyclonic; circulating and lowering the Pressure at the opening, ... effectively reducing the amount of AIR allowed to reach the AIR Jets.

Venting the Orifice with small Hoses or adding a Velocity Stack giving the In-rushing Air enough "Shape" to let the Bottom of the Orifice catch the Stream, ... letting some AIR reach the Main Air Jets and Passages to feed the Air needed to allow the Emulsion Tube to work correctly.

 

Ok thanks for the info.

 

Wow, I need to stop reading this thread.

Now I'm starting to contimplate this idea way to hard. Just for the "how can I do it and make it look like an OEM design" tinkering factor.

 

Thanks for getting the pic back up Rick...that was how I remembered it, but I wanted to be sure

eggzactly camelman....sittin' here in the mid winter doldrums trying no to go entirely stircrazy between school and studies. So maybe a little designing diversion would help to calm the I-want-to-be-riding nerves...

 

So what does an airbox have that pods can't supply.

1. A limited air intake
2. Velocity stacks to shape air into the carburator from airbox

Question: Can these airboxes be opened up with holes say; and be re jetted. To the "added" air?

To say, what is the main factor why pods don't work as well?

I was under the impression one could jet to any amount of air.

What are the limitations to air intake? More air more fuel relative right.

I am sure you are all sick of my theory just want some honest feedback. It seems to work well for me.

It seems clear to me that the only solution to make pods work right is the stock stack. The airbox shape is too convient to really have that much affect on the carbs. Don't get me wrong the carbs are set for the stock airbox. BUT isn't re jetting the carbs possible as long as the stream of air is retained?

 

im not sick of your theory it seems to be the one that actually works with less hassle than other pod setups. im definitely going your way and use the stock stacks..

im sure you posted it somewhere but did you have to rejet?

 

Yeah I re jetted, and drilled the slides w/ the dyno jet kit. I believe the main jets are 132, don't quote me, they are the smaller of the stage 3 jets the kit came with. I colortuned it with the stock pilots, and all of my plug chops came back with a very light tanish color. no specks or signs of lean over hot condition.

 

Re: For Pod Guys & PVC Manifold Guys ONLY !! By: Rick Masse

I must be missing something here...

That obong hole needs to supply a vacuum signal to the diaphragm to raise the slide. If you vent the hole outside of the pod, where exactly is it going to get the vacuum to raise the slide? The carb bellmouth will be subject to engine-created vacuum, but the diaphragm port is vented to atmosphere, a higher pressure region. How exactly is the slide supposed to rise under those conditions? I thought that's one reason why pods make tuning (cv carbs) more difficult, the fact that intake vacuum is reduced. It would also explain why diaphragm vent holes need to be drilled larger when using pods, or jetting up.