Pod Filters?

Ok im going to throw something out there and see if it floats. I have been trying to machine a plastic plug to fit in the horn to block it off and it is proving to be a nightmare due to the slope of the horn intake. I have been reading on several different web sites and forums about tuning CV carbs to pods. The rejetting is a given but they also talk about increasing the vent hole in the bottom of the slide to allow it to rise faster and reduce the up and down jitter the piston gets. No one talks about increasing the intake runners to shape the air flow. Do yall think increasing the vent hole will work in place of the blocking and reventing. Just a thought.

 

However the Cavity gets supplied with Atmosphere is going to be a leap in solving the Lean Condition associated with Pods.

As long as AIR gets supplied to the AIR Jets ... whatever Modification necessary to achieve the end result will likely have a beneficial outcome.

The new Vent just needs to let the Cavity below the Diaphragm Rubber "Breathe".

I suppose a Vent Hole or Slot located anywhere below the Diaphragm will do.

 

Scizor, I am also in the middle of a XJ bobber project, I bought some pod filters for my bike as well, (1981 XJ650) and havnt put them on due to my research and findings about re-jetting... although like some have said even after re-jetting still doesnt run well. my question is did you re-jet your carb and if you did or didnt how does it run. whats the point in rejetting if it still isnt going to run right or maybe worse. Also i have done alot of studying on the air box and have noticed there is what i believe is a vacuum line (i may be wrong). I am wondering what a person would do with that "vacuum" line after removing the air filter box and what damages that may cause... So far i am thinking it will be best to keep the factory air filter system even though it isnt cool looking like the pods. But who knows ive heard alot of people say that re jeting would need to be done for exhaust mods or straight pipes my pipes are cut in half and doesnt seem to have any effect other than louder than the normal electric weedeater factory sound.

 

The AIR Supply to Pilot and Main AIR Jets is more important than experimenting with Shims and Jetting.

Theoretically: You could have a Main FUEL Jet the size of a Fire Hose Nozzle and FUEL >> IS NOT << going to be adequately drawn-up into the Air Stream, ... up the Emulson Tube Center Passage without the AIR surrounding the TUBE to bleed through the tiny holes in the E-Tube to help SIPHON and ATOMIZE the FUEL metered by the Main FUEL Jet.

The presence of AIR surrounding the Emulsion Tube is VITAL to the BASIC FUNCTION of Fuel being introduced to the Intake Stream.

So: JOB-1 = Insure AIR surrounds Emulsion Tube.

Then, ...

Add: JOB-2 = "Shaped, non-turbulent, column of air passing-over the Exit Hole of the Emulsion Tube and Below the Hole Drilled at the Bottom of the Diaphragm Piston ==>> To LOWER Pressure and cause AIR to rush to where the Pressure is lowered.
1. Drawing AIR from the supply surrounding the Emulsion Tube causing Fuel to rise with that Air into the Intake Stream.

2. Lowering the Pressure within the Diaphragm Piston causing the AIR to vacate the Piston and the Diaphragm Rubber to collapse and the Piston with its Needle Valve attached to rise and facilitate Item #-1.

 

The dyno jet kit comes with a drill bit to enlarge the holes in the bottom of the slide. I will check on the size here shortly, my bike w/the stacks doesn't seem to have any lean symptoms, but am very interested to trying the rickcomatic bypass to see if I am missing something.

 

Give it some thought.

Sealing the Atmosphere Orifice and finding "Some other place" to VENT the Cavity BELOW the Diaphragm Rubber is the mission.

If the RAIL holding the Carbs together prevents Modifying the Carb and adding an External Atmosphere VENT ...

Use your imagination and Fabricate some other VENT which will supply Atmosphere to the cavity BELOW the Rubber on the Diaphragm Assy.

 

why doesn't everyone just buy UNI brand pods then that don't cover the orifice? Problem solved...my gosh, enough already

 

Reallly DW? I don't think you understand what exactly has been discussed in this thread, perhaps you should re-read, to try to gather the point.

 

Just remember how much slide/diaphragm assemblies and carb bodies cost before doing any DRILLING.

If you have a spare set of carbs to experiment with, fine. But I strongly recommend against drilling or enlarging holes in irreplaceable carb parts if you have no backup.

 

Yes, really. *I hope that "phrase of the moment (really) dies soon too BTW* There are thousands of XJ's and other bikes riding around the world right now WITH pod filters, including my old XS400J with UNI's on it. They don't neck down inside and have rubber covering the inlet. Just use those if you are struggling with your "tuning".

 

dw- its slowly dieing only to be replaced by another annoying phrase of the moment, SERIOUSLY.

 

:lol:

 

DW do you care to share the tuning process you went thru to get your 400 tuned right to run on pods. We are trying to figure out how and what needs to be done to tune our bikes to pods without going thru all the trouble the ones before us have gone thru. So just saying run UNIs does not give us much to work with.

 

I am not familiar with UNI pods, but if they make tuning easier I can only assume that the mounting boot is either longer or of a consistent and smooth diamater between the filter and the carb. This is the only way that I can see a pod supplying the necessary atmosphere to the vent. Is this the case?

 

UNI's are foam pods. I just upsized the main two sizes, pilots one, and shimmed the needle with a washer. set fuel screws to 3.5 turns and she ran like a top. this was with open headers with slash-cut tips.

 

I looked them up swguy they look alot like pods just the filter material is longer. The intake boots look the same as the pods. It maybe the restrictive intake air the foam provides that would make them different.

 

dw- what do the inside of the uni's look like? Is there some type of tube inside to keep the foam from collasping? If there is a tube inside then that would shape the air charge and may even drop the pressure at the horn needed for the slide to work properly. I can't find a picture of the inner workings of the uni's.

 

they have a spring inside them that gives the filter support. The inlet mouths are the same diameter all the way through unlike EMGO or other pods that neck down inside and cut off the air holes...

 

Ok I would like to know the size of pod filters you guys are running on your 1983 650 Maxim. I know ebay sell the 52 mm but I want to be sure before purchasing.

Thanks

 

Wow is the pod debate still raging? sheesh.