Good news about "pods"

I don't have "pods" on my bike, I have K&N 2372s. K&N makes them for our bikes. I'm speaking of 550s. I have a NOS Mac 4 to 1 and the aforementioned stacks. I went with 6SigmaRacing to put together a jet kit. They ask for your mods (exhaust, intake, elevation) and put a kit together. I told them what I had. They sent me a kit. I used two shims on the needle and went with 130mm on #2 and #3 and 127.5mm on #1 and #4. I adjusted my valves and colortuned. The mixture was in the blue up to 4000 rpm. I am at sea level. My NOS Mac needs re-baffling, but other than that I am running clean. My plugs were decent and just some fine tuning with the colortune and no need to re-change shims or jets. 6sigma is a performance exhaust company that does competition work with cars and bikes. I went all out since I had the equipment and went stage 3. Go with what I stated above if you have similar. If you have PODS all bets off. I have K&Ns MADE for the 550, so can't say what will happen with cheap pods. My bike now gets great response and acceleration and gets to red line really quick. It's wicked acceleration and fun, but be prepared to do some tuning (get valves and carbs right) though I didn't have to change anything internally after adjusting my valves and carbs. Meaning I didn't have to pull carbs and change shims or jets again. ONLY WORKS AT SEA LEVEL AND WITH THE MODS I HAVE, CANNOT SPEAK FOR ANYTHING ELSE.

 

Adding this to the mix.

 

I'm thinking of buying the same filters. What size were the mains and pilots?

 

Only changed the main jets. Sizes listed above.

 

So what exactly is the news? You didn't exactly use pods, per se; and you DID have to re-jet. The only upside I can see is this shop that did the dev work for you.

Does it still pull to redline? Have you run any plug chops to see what is happening at say, 9000rpm? The "extreme" performance you're describing may be at the expense of a high-rpm lean condition. These motors absolutely scream if you run them lean... right until they blow up.

I would definitely monitor your plugs closely for a while.

 

There wasn't the tuning nightmare so many people moan and carry on about, I lucked out and got it the first time around. I was passing along what worked in my situation to other people interested in doing similar. It pulls hard though out the power band. Bike was on the rich side not lean. Lighten up Fitz.

 

after doing some reading on more "pod friendly" sites, if i were to put pods on a bike, I'd put duct tape on the inside of the outside pods facing out, to help prevent from side drafts and the tuning you can do with your legs... it can really lean out the outside cylinders

 

I tried pods but went back to the air box

 

put duct tape on the inside of the outer half of the outside pods, it makes sense if you dont think about it

 

The only problem that ever got solved by using Duct Tape was how to keep sections of heating and air conditioning ducts to stay together.

 

Rick, I find your sardonic humility hilarious.

 

Duct tpe and WD-40 are all you need. If it moves and shouldn't, duct it. If supposed to move and doesn't, WD-40 it.


But isn't the pod theoretically an air duct?

 

please :roll:

 

Rick - not even that. It's why UL 181 tape is now mandated for all duct connections/joints. However, it does work well across mouths. :lol:

 

The sudden obsession with duct tape is starting to sound like a Red Green episode.

 

Can anyone show me one post on this site of where someone put pods on there motorcycle and it blew up from running to lean. I can't find it, running poorly because they can't properly tune yes. Here is a guy who is giving guys who have modified there bike and want to run something other than an airbox an option and right away gets attacked by the stock guys who would never run anything but a stock setup. Why?

 

This is not true! One of my friends from my old job at piper aircraft sent me this. Link

www.rense.com/general89/duct.htm

Sry to keep going off topic but we all fuss about the pod thing. Arguing with people that have made their minds up on the situation gets us no where... Arguing wether or not duct tape fixes things is another story though!!!

 

Well if women don't find you handsome, they should at least find you handy.

 

and it holds race cars together also

 

First off, I wasn't "attacking" anyone.

Secondly, the K&N "single big air filter with 4 holes in it" isn't exactly the same as pod filters, by a long shot; it brings its own unique set of airflow characteristics to the table (which is why #1 and #4 are jetted differently than #2 and #3.) It's more like a really free-flowing airbox.

Further, since it's NOT a set of pods, and it DID require rejetting, my point was only that while possibly "good news," yes, it did not necessarily represent a solution to the problems associated with tuning for pod filters.

For everyone except 550 owners, the only real "news" to be had is a source for jet kits that in this case, apparently worked right the first time. That's great news; I was and would still be concerned about possible starvation issues at high RPMs, that's why I asked. Most pod-equipped CV carb bikes I've had direct experience with tended to fall flat at higher RPMs, and/or ended up being way lean at the top end.

And yes, there have been more than one post from folks who found holed pistons in a motor that had been run too lean. I don't want to see anybody blow up a real nice 550 like that; and I welcome the possible alternative to the stock airbox.

 

There's a bazillion threads on pods. Let's get back to the duct tape.

 

http://www.lowridersbysummers.com/twt/13/index.html


This is what schooter is talking about with the duct tape on a breadbox air filter.

 

Actually, I looked at the part number he gave, and I think it's actually 2 filters, each one taking care of two carbs a piece. Somewhere in the middle of the argument, I'd say. :wink:

 

if anyone gets tired of reading these airbox/pod threads, here's some more
http://kzrider.com/index.php?option=com_kunena&Itemid=116&func=view&catid=3&id=433056

 

Update on "pods", which are actually 2 into 1s

Hey, still screwing with the jetting. Running lean. Was perfect, but got leaner and leaner. It was driving me crazy, but then I realised the temps going up were effecting it dynamically. Running lean will destroy the engine, so just jetting and test riding. That's one thing I love about Rt 50 near my house. I've basically created a race bike with open exhaust and intake. The down side is race bikes have to be jetted for each event according to the environment, elevation, weather, etc. When you get into that level of tuning required for a street bike it is a hinderance. When I get it set for the summer, I'm leaving it and just let it run rich in the cooler weather. Thank goodness I'm not in the hills where I would have to deal with that with every hill and valley. I've learned that the factory engineers have put A LOT into finding the sweet spot that carries over different circumstances. Stock air box design in particular. I think it is much more profound in a highly tuned 550, than say a larger cc engine with a broader tuning band. I thank Fitz for suggesting I keep my eye on the plugs. These carbs are extremely sensitive when you set it to race. As said it's damn near tune it per ride like a racebike. I enjoy working on it and think of it as a hobby and found a site that has OEM equivalent jets for $2 and change each, (jetsrus.com) so I'm not breaking the bank and learned A LOT about my bike with research and hands on. If I wanted a fast bike for the sake of speed and convenience, I would have just bought a newer sport bike. It's more fun when you earn it. That said if I get another bike it will be a sufficiently fast bike stock, and I'm not screwing with the engine. No lay person can ever dream of eclipsing multiple engineers. Not giving up on this bike's home tune, but I'm not opening that Pandora's box with another bike. :lol:

 

Moshumi13, Hey, how did you fasten that one air cleaner on all 4 carburetors? I see the center wingnut but what did the stud thread into? grunt007, 81'XJ750SecaR, Mi.

 

K&N RC-2372
The filters are 2 carbs to 1 filter, so two filter housings. The filters attach directly to the carbs with a hose clamp.

 

Re: Update on "pods", which are actually 2 into 1s

That isn't a race track....it's my gateway to the Ocean!! <LOL> I got a warning on Rt 13...two miles South of Salisbury a couple weeks ago...state Trooper, got me by pulling in front of me with rear facing radar...my detector went off but it was too late...while he pulled off to get behind me I stashed the detector in the console and was REAL nice to him....warning only.....

jeff

 

There are those among us who are interested in pod filters for reasons other than performance. For example, the 900 I have is missing the air box and they are not a common item out here. Also if you have chopped your frame and no longer have room for an air box then pod filters are the next logical choice.

From what I can see the main problem with pods is that they flow a lot more air than the standard air box and filter. The logical thing to do is to jet up to match all that air, but how about modifying the pods to make them present to the engine the same restriction as a standard air box?

I propose putting some instrumentation on a stock engine/airbox and measuring the air flow at a number of rev points then working out a pod system that will flow the same mass of air, such that standard jetting will work.

Has anyone tried something like this, in a properly controlled engineering manner?

And to pre-empt the obvious, there is a cross-flow effect in the airbox and the interaction of the individual inlets is no doubt highly complex but at the very least it is a plenum chamber with a restrictive filter so it should be possible to duplicate it with something like the breadbox filter referred to here, suitably modified.

The last issue to address would be noise. Aftermarket filters are notoriously noisy. The bell mouth on the rubber inlets inside the air box reduce the turbulent flow around the hard corners thereby reducing the noise. Or just run a louder exhaust to drown out the hiss

Any thoughts?

 

The reason Pods don't provide the Engine with the correct Air~Fuel Mixture has much LESS to do with the SIZE if the JETS, ... and much MORE to do with the SHAPE and SPEED of the Intake Air PLUS the PRESSURE and AVAILABILITY of MAIN AIR Supply.

A problem MUCH easier to address with the MIKUNI Carbs on the 900 which have an EXTERNAL Main AIR JET right on the Intake Horn.

Pods and Pod related issues have been the subject of many discussions, here, in the XJ Bikes Forums, ... to the point of ad nauseum.

 

Point being, altering the air flow on a 550 is a Pandora's Box. If you want to open it go ahead.

Haha. Yeah, you're right JeffK, you have to watch out for smoky bear on Rt. 50 and Rt. 13 around here.

 

I hear ya "bobberaha"... I also find it strange to read negative comments within the "XJ Modifications" forum. Whether or not someone is being attacked, very often there seems to be a negative connotation involved with something other than what the engineers at Yamaha designed in the 80s (AKA a modification). If you haven't been to, you should check out http://www.thechopperunderground.com It's a great site dedicated to chopping/modifying bikes.

 

Update: The nature of the airbox

Rick said something about the air actually being an issue in this post and other posts I believe, and after reading it I decided to research it and found out a few things.

Apparently, an inherent design feature of the airbox is to regulate the positive/negative air pressure ratio within the carbs. The CV carbs are also said to stand for Constant Vacuum.

A set amount of vacuum is required for the slide to actuate as designed. When the airbox is removed the negative atmospheric pressure becomes so close to the high pressure within the carb, the differential is no longer great enough to actuate the slide at WOT and to a lesser degree at mid range. This creates the bogging at WOT that Fitz has mentioned.

Carbs stages are activated at throttle positions not tach positions.

The solution that is safest is to either purchase weaker springs (Dynojet includes one in their jet kit for Harley CVs) or clip stock springs to find the rebound/compression needed to allow the slide to actuate with the diminished vacuum. I'm currently clipping my springs little by little and testing. As of this posting I have up to 3/4 throttle, where I had only half throttle before. This is where you will have to only clip a little at a time. If you clip too much the slide will "bounce" because the resistance in the spring is too weak and it will shoot up and then come back down trying to find the sweet spot in vacuum. This will repeat rapidly until it settles or you back off the throttle.

I would not advocate drilling out the slide! If you go too far with the springs, they're cheap to replace and you can then back off from where it started "bouncing" with the new one. The slides are rare and expensive.

Here are a few links about CV carbs in general:

ttp://www.rhinoforums.net/hunterworks/2 ... -mods.html

http://forums.sohc4.net/index.php?topic=5410.0

http://www.hondanighthawks.net/carb14.htm

http://www.bikerenews.com/Stories_Archi ... etors.html

 

But why clip the springs when you can use bread wrapper ties to "coil bind" them (partially) which is reversible if you go too far??

 

A person can approach it in whatever manner they see fit. The end game is to create the adequate +/- pressure ratio. Also, you would have to apply the ties to the upper spring to avoid friction, mechanical interference and binding.

In my case the springs are already down to 3/5 their original length and it is just stating to actuate the slides. The +/- ratio is slim and the vacuum is very weak, so the spring has to be just as weak or slightly weaker. That would be a lot of tying up.

 

You will still have to deal with eliminating Negative Pressure at the Atmosphere Vent at the top of the Intake Horn.

Net Negative Pressure at that Atmosphere Orifice:

Lowers the Pressure beneath the Rubber Diaphragm making it more difficult for it to collapse against the Intake-caused Low Pressure variant upon the hole at the bottom of the Piston.

Atmosphere needed there, to supply Air to the MAIN AIR JET which supplies Air to surround the Emulsion Tube, ... necessary to effect an Up-draft Siphoning and Atomization of the Main FUEL Supply is deminished, ... causing:

The Fuel Supply to be diminished -- ( The Lean Condition )

Because:

The Diaphragm cannot evacuate and fails to fully rise.
The Needle fails to fully withdraw from the Tube.
Any Fuel which does enter the Intake Stream isn't atomized for efficient combustion.

You need to do more than just put-in weaker Springs.

 

You're "Because:" section states why the springs need to be weaker than the vacuum. I.E. the spring is too strong to allow the slide to compress with the +/- ratio as it stands sans airbox.

The other method is to enlarge the vacuum port, which is dicey.

You have a lot of critiques, but no solutions, Rick. I'm in the process of figuring this out and relating my findings. I am seeing real world results. I'll take results over theory.

People that spend all their time humming, hawing and pontificating never get anything done.

 

Every so often, another crusader comes-along and says they are going to be the guy who figures-out how to afix Air Cleaner Pods to Constant Velocity, ... (Constant VELOCITY --- Not --- Constant VACUUM) Carbs.

They look so cool.
They must be easy to install and run.

Here it is. 2011.
And your the guy; this time.

Good luck.
The process began 31 Years ago.
You'll take results over theory.
There's the rub.

Until you thoroughly understand the theory; how do you expect to get results?
Experimentation?

Please read this article.
Your attention is directed to the Paragraph near the end titled:
"Carb Venting".

http://www.drpiston.com/Cvcarbs.html

No.
I don't have a solution.
Nor, am I aware of anyone who actually does.

 

You drill another port, incrementally, that is fillable with JB-Weld (just trying to help) This gives a quicker reaction time.

 

This thread was started to share my experiences with putting open exhaust and intakes on my bike. Information to use or not use for people doing, or thinking of doing the same thing. Nothing more and nothing less.

The same thing some of us are doing, or trying to do, is done thousands of times to Harley CVs, and I got a hunch they aren't being hounded by other members of their forum.

If you're going to stand up against something, stand up and spread the word about something that will make a difference in the world. The anti pod argument has been beaten over the head of the naive that stray from the path of "righteousness" enough already. We get it! Now, if you please, pipe down and leave us to our toys.

 

@TimeToRide

Enlarging the vacuum port or reducing spring resistance has that effect when the carbs are operating normally. Because the vacuum will be stronger or the spring will be weaker allowing the slide to raise faster. When the slides aren't operating normally because of low +/-, it will allow them to function properly. Get the lift that is needed.

 

Hold on now. This thread was started, according to you, because you had "good news about pods."

Apparently that isn't the case. What IS the case is that you are waist deep in the "trying to do" phase, like so many others before you for the last umpteen years.

What Rick is trying to do is explain some of the SCIENCE behind what it is that you are trying to do and why you're seeing the issues you are.

Comparing the attempts to make pods work on a four-cylinder, high revving motor with 4 CV carbs to the fitting of a "pod" to a single CV-equipped, low-revving twin is evidence of the fact that you don't fully understand the science behind what you're actually up against.

Rick is just trying to explain the battle you're having and why you're still having (and will continue to have) it.

Be sure to let us know if you actually do succeed. Because, despite the optimistic title of the thread, it sounds like you've got a ways to go.

 

8O :? :lol: :twisted:

 

Interesting thread.....

You would think that the solution would be to add more fuel to remedy the lean condition (rejet, shim needles, pilot jets,etc). However, Rick and others have pointed out in the thousand threads before this, this lean condition is not caused by the failure or amount of fuel delivery (tuning, sync, blocked passages, etc). Instead it is caused by the poor vacuum condition that the pod creates. This poor vacuum does not allow for the proper amount of fuel to be sucked into the chamber or the proper atomization of fuel to effectively combust. Re-jetting + shimming will only increase the amount of improperly atomized fuel.

Look at my bike. Yes it runs and rides nice. However, it is a b***ch to start (improper fuel/air ratio), lean - no matter what I do to it (too much/too turbulent air), backfires (improperly combusted fuel), and when it's good + warm, it want to idle @ 4500 rpms (hanging slides due to improper vacuum)

When you or someone else finds THE ANSWER, please let me know! Although, I doubt it's gonna happen, unless maybe you would stick Fitz, Robert, Rick, and a few others in a garage for a month or so. Someone told me this a long time ago - not in relation to my bike, but it certainly applies here.... "A team of engineers with years of experience in this area designed this over the course of months, and you think that you can do better than them in an afternoon w/ a case of beer? I think not."

Cause I gotta agree on one thing... anything looks better than that clunky hunk o' plastic stuck in there. I do agree that appearance is important, but it's not everything. Every Harley owner I know will chrome anything and everything (i bet that they would chrome the tires if they could). But you know what? It's all cosmetic. Ask one of those guys to make a mod that will damage the bike in the long run, and see what they say.

Now if you'll excuse me, I have an airbox to put back in.

 

I like my airbox but I was reading on other website that if you put an extension of 2 inches in between the pod and the intake of the carbuarator that makes the turbulance go away and will run good. I think is worth to try.

 

This makes sense as it would help to reform the air and may help restore the propper pressure around the main air vent. I have seen some have success running the stock intake boots on their pods which is what I plan on trying when my dynojet kit comes in.

Cheers
Dave

 

Just as a note to the curious, my bike runs fine. It idles at 1200, goes thru all the gears, fast throttle, tan plugs at idle and mid range, and gets to the bottom of the speedo in 3rd gear. I could easily leave it where it is.

Update: Checked plugs @ WOT and they are tan, too. All the action just takes place at the front half - 3/4 of the throttle. Not something I noticed until people started talking about airflow and WOT after my post on chasing the lean condition that I realized was weather related. Afterwards, I took my bike out and checked it out. That is when I started looking into all these +/- pressure scenarios.

 

SOUNDS GOOD!!!

skillet

 

Update:

Not good news. Clipping the springs only allowed me to get to 3/4 throttle. Save your springs and do not get into drilling the slides unless you're adventurous.

3/4 throttle was the best I could get. Slide and spring altering together MIGHT find what you are looking for, but slides are expensive and JB breaks down in a constant environment of gas. Hard brittle pieces are not advocated in carbs or engine.

As I said before, podding 550s is a pandora's box. It's an adventure you must wage yourself. You could listen to people that have come before you, but who does that?

My setup is at sea level, with east coast humidity and an average 85 temps, it ran fine with stock springs, only the throttle was condensed to within half. Not noticeable if you're not looking for it, because it behaves as any other bike would. Just more sensitive throttle.

I had everything you want in a bike. Just not WOT. Hit me up with a message if you have questions. I learned a shit load about tuning these carbs as far as jetting goes. I'll help if I can.

Four spacers on the needle
137.5 main jets
hand tuned air/fuel

I do believe that the fuel makes up for the lack of vacuum. I could almost watch the needle go down.

All stages had tan plugs. Idle, mid-range, WOT

This held true at the lowest spring level, but it still registered as a rich environment, due to the false lean condition created at WOT due to the lack of vacuum.

I also adjusted the valves, synched the carbs and they are clean. It's not impossible to run them, but your bike has to be straight to even touch the carbs.

I've pulled the carbs so many times to adjust, I could do it in my sleep. I'm tired off chasing. It gets old. Especially with such a small window to find.

 

love it