Pod filters, yes, I stepped in it on purpose.

Total pressure = Static pressure +Velocity pressure. Its the same either negative or positive. In this case total pressure does not change thats because the displacement of the engine is the same but the free flowing pods make it easier for the air to fill the void the air flows in faster VP goes up if VP goes up SP goes down that means there is less vacuum to pull the fuel into the engine. Thats why the fix is to put in larger jets its not to get more fuel its to get the same amount of fuel you needed before but now with less vacuum. Suck on a small straw a coffee stir straw then suck on a big straw but try to use the same amount of suction, stuff coming out of your nose? So why does putting a (velocity stack) seem to help? By adding surface area to the air stream you are creating more SP, just physics more surface more static. PS its not a velocity stack its a piece of pipe

 

Soo check it.
What if! (and ive been thinking about this for a while) You took some PVC or something similar and connected 2 carbs to one pod, or all 4 carbs to one pod?? Increasing the air flow because of the pod(s), but not SO much as people do with 4 pods 4 carbs??

 

The major difference in pods and the stock airbox is the length of the intake runners. Pods have short runners and do not allow the incoming air to form and kind of shape. Adding the stock intake runners to the pods allows it to shape the incoming air and increases the SP of the air charge. Street Brawler added the stock runners to his Pods and increased the Main jets and says his bike is running great thru the full range of RPMs with no flat spots.

 

please read my post about the air flow through pods/box in one of the other million pod threads going now. pods do not introduce turbulent air to the carbs.

 

Pods, pods, pods! Everyone is nuts about pods here and one way or the other there are a lot of valid arguments and hypothesis/proof as to whether they work or not. When I bought my '82 750 Seca I had an expressed intent on equipping it with a pod setup. I just spent $500 having the carbs rebuilt, MC/brakes serviced, tune up and the like by a Yamaha factory certified mechanic of 30+ yrs and he says pods will be fine on it. Then I read all the pros and cons of it here and many thoughts come to mind. I am by no means a techie in the old school but I understand what you technical types are saying. I myself think the stock air box is a bulky looking piece of intrusive junk, another reason for the pods.

One thing I've not seen mentioned in this thread is a custom pod/air box solution. My idea is to have a sheet metal box fabricated that houses the pods and would funnel air like a duct or ram air system. To me it seems that would address the turbulent air situation by smoothing out the air flow and channeling it directly into the filters. It would also create some restriction and have all cylinders pulling air from a common location with a like pressure correct? Is anyone running a setup like this or have any design ideas to do so?

 

Search function, use it.

 

Link, maybe StreetBrawler? What have you seen/read/done? Im bout to equip pods onto an XS1100 cause it came with the bike(s) and no airbox.
-Chris

 

There are a bunch of discussions on here. Just search for pods and have a couple hours available to read.

Here's a link- http://www.xjbikes.com/Forums/search/mode=results.html

 

Give me $500 for $40 worth of work and I'll tell you whatever you want to hear too.

 

The "Turbulence" issue gets worse as RPM's rise.
The 1 - 4 >< 2 - 3 Intake pulsation worsens it.

Good luck.

 

I'm going to try the pods with the stock intake runners as Brawler suggested. If things don't work out, I guess I'll be cramming the fact. airbox back in and selling the pods on eBay. I'll report back on how this works once I get them and install them.

 

I lean towards pods because they free up so much space below the seat area that could be used for other things - like a toolbox etc.
The only reason I haven't done it yet, is because I haven't done the calculations of exactly how much pressure the stock air intake creates. Nor do I know how to measure this. But I guess, when you know how much the pressure is over the air intake, it could be replicated on a 1 or 2 pod intake (using pvc tubing).

 

Do considerably more research before you leap into the void.

 

I wish to thank you folks for posting this. This has been VERY educational.

Seems to me it boils down to the salt easily.

** Start wth this .... Pods look cool.
** Pods reduce horsepower if not really given a LOT of attention when initially setting up.
** Pods (generally) run no worse than stock, but produce less power overall. Until we get into screamin RPM levels. Ride it like a two stroke and it'll go like the dickens!
** Pods can be made to run ok, but even then you'll still have a bit crappier powerband/useable power.
** So you'll generally lose a bit of power, and your bike will still behave about like stock.
** End with this ... Pods look cool.

So if a person wants *that look* it can be had, however there will MOST LIKELY be some sacrifice of power. Rideability can still be had. So all in all, it sounds like a trade off. Looks for a bit of performance. If you're not too altruistic, pods are fine.

Have I got it then?

In any case, my bike came with pods/stock pipes. The right hand pipe is blueing at the head. Obviously the bike is NOT set up for the pods that the PO put on it to sell the bike. I'm currently seeking out a stock airbox that I'll stuff a K&N in to.

Face it guys ... these ain't no CB750s or RD400s. Goofing with airflow in these "EPA" CV equipped engines is kinda like playing in a toilet .... you might get some shit on your hands!

Issue solved for me.

Thanks TONS for this thread.

Abeja.

PS: Make this an "article" so newbs won't rehash the issue Just sayin'.

 

Let me first say I love the input from the foot soldiers and not from the palm readers...that is where these threads get lost, speculation swallows all the fact. :x

Abeja , you are all over it. But there are a few flopping fish to fry even after all that. :lol:

I love the effort but need more beans on the table to close the book. I do question the dyno results as a whole. You can not claim a scientific study without a set of scientific results. What was the humidity, barometric pressure, maybe ELEVATION...umm, absorbstion or drive dyno, corrected numbers or raw?? I was a performance parts builder so I had to play with variables....and lets just say they vary, hahaha. :wink:

My point is, bring your High HP setup to my neck of the woods and you are running lean and running a full second slower in the 1/4 mile and HP will lose a solid 10-15%. I live at 5k', not saltwater at my toes, so I have a perspective that is not universal, just a different, but legitimate angle. 8)


The horse asked for another 2 cents.....

I can not sell an XJ for 3 to 10 times its OEM value with an airbox to the "GENERAL POPULATION", plain and simple.

I can not sell a bike that does not idle or run strong, regardless of air intake setup and regardless of make and model.

So for me, a good strong running bike with good compression and proper valve adjustment DOES accept Pods well. So I lose at MOST 5% hp at any given RPM...at least thats what is being touted. Small price to pay for a nicer look like Abeja said, if your not a purist.

 

I'm not exactly sure if I follow the discussion related to Pods just preceeding this Post.
Breaking it down seems to indicate that the main reason Pods are installed are because they "Look cool'.
Yes, they do.

I'm not sure I understand why anyone would suggest taking a Bike with CV Carbs, Fixed Jets, Fixed Timing and only Pilot Mixture Screws to Externally Adjust anywhere near a Dyno.

The ONLY Adjustment to be made without removing the Carbs is Pilot Air-Fuel.
Adjustments to Timing and W-O-T Mixtures cannot be done by Reprogramming the Software.

The adjustments one makes to their Bikes after putting-on Pods are NOT done to IMPROVE Performance.
The experimentation one commences following the installation of Pods IS done in an attempt to RESTORE Performance sacrificed to look cool.

The problem with the discussion of Pods is incomplete without well-known Caveats.
Unless you inform the party inquiring about installing Pods about the complications which arise when abandoning the airbox for cosmetics over performance, ... you're NOT acting like Motorcycle Mechanic.

You're acting like a Shoe Salesman working straight commission.

"I know they're a little tight and make your feet hurt, Ma'am. But, look how nice they look on you!"

 

? if i may, still in the process of my 80 XJ650 hardtail build. I kinda faver the velosity stacks over the pods myself, just curious if my stocker 32 CV carbs are ok with a rejet kit, or look into different carbs?

 

If you want to build a bike that is going to fly and not have you pulling your hair out trying to get immediate throttle response throughout the whole power band, ...

Get a set of Performance Carbs.

Bolt-on.
Ready to Go.
Pods friendly.

The only thing you're really going to need is: A Cosigner!

 

In the early 80's when WFO and I were dating he drove a 1978 Trans Am. Of course he put on a big velocity stack and Hookers on it. At one point even a double pumper. The thing ran horribly, sputtered from stop lights, and often smelled very rich. But that was secondary to the cool factor the car had for him. Keep in mind that he represented 99% of the American street-cruiser crowd that large chains like The Super Shops made their livings from. Black Jack headers for a Camaro were $50 bux. So since the dawn of go-fast, guys have been driven by their little heads when outfitting their cars. You KNOW I'm right about this. So the cool factor of pods outweighs the hassles and poor running that most pod installations produce. So sayeth the little head.

I'm not saying girls are any stronger than men when it comes to vanity items. I'm well aware of the cost of vanity, and I'm just as gulty as any toupee-wearing crisis-bound man with a fire engine red sportscar and a trophy wife. I just serve a different part of my brain than the boys do when it comes to chasing things down to put on my bike that will attract attention an win approval. Just thought I'd get it out there that I'm no better than the stereotypical over-compensating-male .. so I get it!

I like how pods look, they remind me of seeing Kenny Roberts in 1977 at Ascot when he had this TZ750 (2-stroke TRIPLE) flat tracker. It had these wonderful pods that stick in my mind. That bike was evil, only he could hold on to that monster. AMA outlawed it before the very next race. But I certainly remember that bike, and how it looked with those pods. It looked like a very pissed off hornet. With dirt track tires!

Even with all that, I'm not willing to go the full-mile and do up the carbs to handle the pods (that came on my bike) correctly. I'm also not willing to have it run ~worse~ than Yamaha tuned it. I mean, I remember how WFO's Trans Am ran, and it was always "don't it fargin sound bad ass, babe?" (of course at 18 years old I LOVED his car .. and to me it DID sound cool, so the fumes and the stumbling/etc .. were of no consequence). And no ... I don't really want that this time around. Hehe! I ~know better~ as it were. Cool means something different to me now than it did then. "Loverboy" on the casset player notwithstanding! So I'm going to put either the stock airbox on it, or I may work up a cool manifold that will use a single airfilter.

WFO was telling me the other night that he was thinking that on these 80's EPA bikes, he was saying that it's easiest to leave everything between the airbox and the exhaust *log* alone, and keep your messing around limited to everything before the airbox and after the exhaust log. Keeps the factory tuning intact. Um, pretty much. Seemed to make a lot of sense to me ... y'know once you sorta ~crack the system open~ you start a chain of events that .. while cool in the end .. is very costly.

Sorry I'm such a chatty cathy, we've been working on my bike all weekend and had some fun company/help at the shop and a few (heehee) beers. Two sniffs of the bar rag and I'm stooped! I've survived the end of the world, I'm all amped about the bike, and just very excited about how it's going to look and the direction it's *decided* we're taking. My first highway capable bike! I'm scared to death and excited beyond description!

Abeja. (pronounced ah-BAY-ha .. jsyk)

 

Check out a Seca 750 - Kenny Roberts style
(looks like velocity stacks - sold for $3,500)

 

My 2 cents on this constantly regurgitated issue:

1 - Yes, pods look cool (This one is the least of my concerns.)
2 - Pods make removing and re-installing the carbs much easier
3 - Pods eliminate a very large airbox assembly, who's space could be better utilized for placement of battery, tools, electronics, etc., allowing you to really simplify and clean up your set up.

-BUT-

Pods on a CV carb'd bike make it a pain to dial in and at the expense of a certain amount of power.

-SO-

I'll just suck it up and run the damned airbox and deal with the shortcomings that come with it, cause at least THEY are easier to deal with than the alternative.

 

It's all out there, in less pages, on this topic finally.

In the end this is an 80 hp bike and a margin of 10% loss or gain depending on how you tune it. No matter what ANYONE does almost ANY equal cc fuel injected bike with eat the OEM XJ for breakfast.

Like Abeja mentioned I would never have the same impact my bike has now with an airbox. Sometimes it's actually better to look fast than be fast, In a weird kind of way, especially if were not talking about going from a 10sec bike to an 11 second bike. (Then I would wholeheartedly agree with the purist)

 

Hey all...

I am new here but thought I would dive into the fray...

I do custom bicycle restores... as well as modding some of them with 67cc 2 stroke motors...

These are cheap motors and the tolerances are all over the board... so there is no right way to do anything... lol... there is a lot of trial and error... and a lot of tinkering...

For some folks its all about the looks and for some folks its about getting the most out of that little motor...

I also make Art-cycles... basically 2 wheeled rideable art... with these it is all about the looks...

I said all of that to make a point... lol

For those that are about the looks... and the look they want includes pods... I say go for it... and for those that are about performance... go for it...

It would be nice if there was a pod thread that was just devoted to getting your bike to run well with pods... You performance guys say that you cannot get top performance with the pods... I get it... but if I want to use pods because of the look... I am going to... and a lot of others have and will do the same...

SO... a thread for us crazy folks that want to use pods would help... lol

Peace to all

David

Thanx for the thread and input so far as well...

 

Maybe I should just put it this way... my bike came with pods on and an airbox in with some other parts.... I don't think id put pods on if I got the bike stock... but they are so darn pretty.... and I made a halfassed attempt to.put the airbox in andit didn't go well. So.... ill just settle for my lack of performance for the time being

 

Just recently got my bike finished with the 1196 Wiseco piston kit, Dyno jet kit, rebuilt carbs (120 mains) and it starts, idles and runs like a holy terror. No problems with anything so far with the exception of a stuck float on carb #2. LOL. Anyway, love them, love the sound and performance and BTW, still have the stock airbox that came on the bike.

To each his own and I don't knock anyone for keeping it stock. Be safe out there, everyone!
Jamie

 

Pods make me think of back in the 70's when electric starters were new out on Bikes. Right away the Harley boys said that anyone that had a electric starter on their bikes was a SISSEY! Today most all Harleys have electric starters-SISSEYS! I believe firmly and respect greatly every person with a bike which does his or her own work on their bike and actually becomes a part of their bike. It's the individualness that each bike developes as it's owner puts themself into it that makes it special or sometimes a piece of junk! A XJ 750, Seca can smoke a Harley, does that make it better? Not in the Harley owners mind for sure. Does it really matter if it looses a second in a 1/4 mile? Not unless you are racing for a cash pot. So, whats the difference? I guess it's what the owner wants out of the bike. Usually to look good to him or her and get them from point A to point B in style. grunt007, Mi.

 

Whow, I must say on the subject of Pod filters you guys have sure made my day to say the least. When I started restoring my 81' XJ 750 Seca R the first thing I got rid of was the air cleaner due to the way it just got in the way of pulling the carbs and I went and ordered Pods. They look great on the machine but I have not had it running yet with them. I just originally deduced? that the Pods would make it much easier to work on the carbs since I forsaw right off that the way I like my bikes tuned that I would be going through my carbs quite often. Now after reading all the right ups in here on the subject I can see that the Pods are probably not the way to go. Thanks a lot since when I pulled the air box out I broke out a chunk on the one side of it but either way you have me convinced that Pods on this particular bike are not the way to go. Now I am going to have to figure some other way to modify this setup other than Pods. You have probably save me a lot of grief although I must admit the Pods are sure CUTE! Now I just have to find another AIRBOX! I guess CHALLENGES BRING OUT THE BEST IN US ((( Thanks again guys for the insight you have given. grunt 007, 81'XJ 750 Seca R, Mi.

 

Hey Grunt, you want to be the first to try something ?
Make up a manfold from plastic plumbing pipe, so you have 4 connections to the carbs one side & 4 to the pods on the other, this will form a chamber for the air to 'mix'

 

I think that many folks here missed the most important point that I had hoped to convey way back when I began this thread. The pods will work fine and will even possibly give you an increase in power IF, and thats a very big IF.....you use LARGER CARBS!! To simply install pod filters on the stock carbs will not, according to the experimentation that we did, give you anything more then a headache. Some may get different results so again, I'm not going to argue about it but hopefully, someone will try a set of 36's or 38mm CV's with pods and they will post up their results.

Honestly, I'd love to see someone install a set of slide type carbs on a XJ and see how easy it is to tune. If I had a "spare" bike, I'd do it for fun but my only other 4 strokes are a 350 honda twin and my vee strom which is EFI.

It is good to see guys trying things and thinking....that's what improves the sport for everyone.

Wiz, didn't someone do that a while back using 3" as the inlet header and 1-1/2" outlets to each carb? Maybe I saw that somewhere else but I thought I had read it here somewhere.

jeff

 

Well guys, thanks for the imput but for right now I have to just go back to the basics until I see just how much is left in this engine. The PVC pipe thing sounds plausible but I don't presently have a single carb of the right size to handle it and PVC pipe and heat don't really strike a happy note in my mind. i think if I one day consider trying that approach at the least it will be schedule 80 pipe or possibly brass sodered.
On the subject of the slide carbs with the pods, for me that sounds like it could be a winner but I would have to do some studying on the subject of just what size to use and then there is the cost factor of obtaining more carbs, guess one day hopefully this summer I will have to visit the salvage yard )))))) I am sure that once I get this bike running and get a feel for her weakneses then I will be much more aggresive of making modifications to her. The nice thing about these older bikes is that they were built to last unlike the new ones. (((( For example I have found out that I can put much more heat on the float bowls on my XJ to break loose the drain plugs then I would have ever imagined possible. When the old are rebuild properly as with farm tractors the user can look forward to getting many years out of them with out spending a fortune each year on them. At my age old re-done is better! grunt007, XJ 750 Seca R, 81' Give me something I can ride down on a highway if necesary-laying down! Only time I ever got stiches on a bike was on a small one which just disappeered out from underneath me-THAT SUCKS!

 

Is this the image of a Mikuni or a hitachi carb?

 

Going ONLY by the fact that the pilot (fuel) jet is so deeply recessed, it looks Mikuni-esque. Not exactly like the Mik's in the 550s, though--- the pilot AIR jet is in the throat, not up top like in the BS28s.

(Mikuni BS28 exploded view: http://xjbikes.com/Forums/viewtopic/t=31061.html)

If it's a Hitachi, it doesn't match the ones I've seen exactly either (again, the pilot fuel jet isn't the same.)

Plus the float level spec is somewhat unusual.

What book is that from?

 

Going ONLY by the fact that the pilot (fuel) jet is so deeply recessed, it looks Mikuni-esque. Not exactly like the Mik's in the 550s, though--- the pilot AIR jet is in the throat, not up top like in the BS28s.

(Mikuni BS28 exploded view: http://xjbikes.com/Forums/viewtopic/t=31061.html)

If it's a Hitachi, it doesn't match the ones I've seen exactly either (again, the pilot fuel jet isn't the same.)

Plus the float level spec is somewhat unusual.

What book is that from?

 

Because the Pilot screw is on top I tought it was a Hitachi but then I found this site and I got more confused.
http://www.drpiston.com/hitachicarbs.html

I am sure I have Hitachi's on my 750 seca but ther seem to be a few versions out there.

 

Unless somebody switched them, you should have Hitachi HSC32's.

Pilot mixture screws are on the top of both Hitachi and Mikunis; but YES there are all sorts of other versions out there. The Mikunis on the 550s are slightly different from the Mikunis on the 900s which are both different from the Mikunis on the 650 Turbo; I'm sure thare are just as many variants of Hitchi out there on other manufacturer's machines.

So what book is that page from?

 

I don't know. Is not my post.