air filter pods vs stock filter box

I was just wondering do the pods allow better flow to the carb?(after rejetting the carbs) i have herd both sides of the argument. Some people say that they do some say that they make the bike run worse. What do you all think? i am thinking of doing it to my 82 xj650 seca. i realy dont wany to spend all the time to put the pods on and have the bike run bad.

 

Unless you are going for the "pod look", stick with the airbox, maybe with a K&N filter because you won't get more than the stock 72 horsepower without balancing out the exhaust, and re-jetting, fine tuning.

Want to find out if it'll run bad? remove the filter and airbox lid and take it for a short ride. Tell us what happens.

 

tell you what... you can give me all the money you will spend on jets... at 16 for four of them.. you may try 2-5 times... that adds up, then you can come and shovel snow at my house.. maybe make a nice little track where i can ride my maxim in circles at the same or better perfomance than you will ever get with pods.... Sound like a plan?

The only excuse to put up with the hassle of pods is if you're chopping your bike and need the room

 

TIME, be nice.

The CV carb is a very carefully balanced instrument that can provide almost fuel-injection like performance IF operated in the proper environment. Part of that proper environment is a carefully constructed intake tract that increases velocity while LIMITING volume. This balance is what the airbox provides; take that away and the CV carb becomes a runaway bronco that becomes very difficult to tame.

You can mess and mess with these motors and unless you put in larger pistons or hotter cams you're not going to out-engineer the guys that designed these things. You can NARROW and MOVE the powerband, you can't widen it; Yamaha got it damn near perfect.

If you really want your bike to scream, TUNE IT 100%---valves, carbs sync'ed, balanced, colortuned and tweaked.

 

I know I'm evil for doing it but I switched to pods when the XJ900 I bought a few years ago had a trashed airbox. The PO drilled dozens of tiny holes in the airbox for god knows what reason. I tried filling the holes with plastic well but existing hairline cracks eventually led to real cracks, which led to a trashed airbox. Yamaha Canada told me I had to order a new one from Bike Bandit in the States. After currency exchange rate, taxes, cross-border tariffs and shipping, it came to almost $300. That's on a item that's listed at $98. on the Bike Bandit website. Now I wish I'd just bit the bullet and bought the airbox. Instead, I undertook the arduous task of installing pods. I had a set RickOMatic had sent me for my 650 Maxim but they were too big for that bike. To get the set-up right I had to do countless plug chops in each gear at various rpms, repeated color tuning, repeated carb synching and demonstrate the patience of a saint. Despite all that, it's an exercise compromise. And I tell you, my neighbors got good and sick of me going into and out of the driveway endless times to do my plug chops. The best result you can hope for is a bike that runs as well as a well-tuned bike with an airbox. You can move the powerband around but you're working with the same engine so that's limited. For example, my podded XJ900 has more power in the mid-range but I had to sacrifice some down-low power to get that - hence the compromise. Also, you don't want to leave a podded bike in the rain since you could end up with water in your pods and worse, in your carbs. So I carry a thick plastic bag to cover the pods if I'm parked up at work on rainy days. Although, you can get covers for the pods that do help somewhat in the wet.
Suffice to say the bike now runs well but installing pods is not something I would do unless I had no choice. Next time, I'll just buy the bloody airbox. However, my neighbors son did say the bike looks cool with the pods. I guess that made it worth the hassle - NOT!

 

The Mikuni and Hitachi "Round-Slide" (CV) Carbs are designed --> DESIGNED to need the Stock Air Box and Rubber Boots.
Why?
Because the 4 Carbs SHARE the Outside Intake Air regulated by the Cubic Feet Per Minute of Intake Air allowed to be pulled in through the Air Box Intake Port.
That amount of Intake Air ... Enters the Air Box.
Gets filtered.
Then, enters a Plenum Space where the Total Volume is divided to Supply ALL 4 Carbs.
The Divided Air Supply is drawn to the Carbs through Rubber Boots which act as Velocity Stacks ... Shaping the Air Flow and eliminating turbulence sending the Air Flow to the Carb.
The accelerated Air Flow passes through the Intake Venturi and across the top of the Emulsion Tube where the high-speed column of air creates a negative pressure variant which draws-up Fuel with the Auxiliary AIR from the supply surrounding the Emulsion Tube which rushes to fill the vacuum.

Pods do not:
Shape the Air
Speed-up the flow
Reduce turbulence
Cause a Pressure Variant
They do:
Allow too much air requiring experimental jetting to maintain Air-Fuel Ratios.

 

It's very true. PODS are not a performance booster. In fact they make fine balancing of your carbs next impossible. On the otherhand, with the right modification to the rest of the bike they do look great. Don't pod your bike unless you're doing other things to the bike to give it that retro look.

I was going to pod my XJ650 maxim cafe racer and I struggled with the decision. In the end reliability and performance ruled out and I kept the stock airbox. The pods would have suited the bike but I didn't want to break my horses leg before my journey through Eastern Europe.

In the end I don't regret my decision. My bike ran very well throughout the trip and I plan on driving it from Croatia further east this summer. (Perhaps Istanbul? Maybe Odesa?)

My advice. If you're an in town rider and you're doing a high quality modification (cafe racer or metric chopper perhaps) then POD it and live with it. If you're just doing it because you think it's an easy way to give your bike a bit of a custom look then forget about it. It doesn't look that good on a stock maxim or seca and you'll pay in the end with harder maintenance.

That's my two cents.

Style vs. function

 

Sigh...

On a 750, does the engine have to come COMPLETELY out of the frame to install an airbox? Assuming you could reassemble it, could a box cut in half fit back in there, or would it have to be much smaller?

I simply can't understand why so many people hack these things up.

 

Yes, a cut box will fit back in (cause thats what the lazy po of my bike did!) But that lets unrestricted, unfiltered air into the system. I took an old tire tube, and siliconed it over the cut.

 

sushi; the bottom line is sadly, yes. I feel your pain. My beautiful 88% original '81 Seca 550 has a disintegrating airbox. It's literally coming apart at the seams, and is impervious to all forms of adhesive known to man. I'm postponing the inevitable with black RTV. I HAVE the replacement airbox ($10 off eBay and it is PERFECT) but the G.D.M.F.S.O.B. motor has to come out. It's not worth hacking one up and trying to glue it back together. Besides, while you have the motor out you could fix that chain tensioner.

Here's a thought: Doesn't your Seca have like a bazillion miles on it? Why not go find a low-mileage mill to drop in there, and while you're switching you can install a new airbox. Then use your original motor for parts, or rebuild it but it's probably not worth the cost. You can find under 10K motors for usually less than half what a full rebuild would cost in parts alone. If the rest of the bike is in good shape, it's what I would do. (Actually, with two of these birds, I've been shopping for a spare motor.)

Just a thought...

 

It's a good thought but I thought the engines were hard to find? Well I'll keep an eye out then.

 

NOTHING is truly difficult Grasshopper but most things require patience. You might sniff about salvage yards like http://www.motolane.com/ Clint is good people, by the way. I've bought a bunch of stuff from him as have other members. eBay is always there but it's not the only resource.

 

I concur with BigFitz. Or you could try taking off the carbs and manifold rubber and it might be just possible to squeeze the airbox into the frame with a lot of persuation. Or you could end up bust the head off a manifold bolt or 2 and then you REALLY do have to take the engine out to drill out the busted bolt!
Yeah, like I said about BigFitz...

 

When I first got my XJ650 82, I put pod filters on for a number of reasons: the old rubbers were cracked, the airbox was cracked, and the pods looked better. I had the carbs professionally tuned and it ran beautifully. however, i repaired the airbox and re-installed it, tuned the carbs myself, and it runs great. reasons being i was told to do so was better for the engine and running, also i live in a very dusty area, and paper filters are very expensive.

to tell the truth the bike runs the same either way. go figure...

 

This is what I've heard alot of. Pods one one of these bikes CAN make a difference, but as was said above, you most likely won't see any performance gain without doing some other, rather extensive, mods, such as exhaust, possibly cams/other engine work.

On the other side of the coin, personally I really like the look of pods. And I know there's been people in the past on here who were able to switch to pods without rejetting.

 

My carbs are stock. I have a wee bit of popping on decel, and the dang thing will BARELY idle without the choke. At the very least, I need to open, or up-size my idle jets.

I was looking into the cavity in the frame left by the missing airbox. That'd make one hell of a storage area without having to add side bags. I think I'm going to fab something up so I can use the bike for small errands.

 

Yes, popping out of the exhaust when you shut the throttle down is a sign of running lean.
I cured this issue through numerous plug chops.

 

But my plugs are perfectly tan. They look like the tan set shown in the thread "pipes turning blue". I think maybe it's more a function of the Supertrapp exhaust I'm running.

Cursed pods and supertrapp.... I also must keep the tiniest bit of choke on, or the idle fades and the bike stalls. Here's my question: Is the idle circuit dirty or is this more a function of needing to up the idle jet size because of the pods and muffler configuration?

Do I even need to replace them or should I shim them and turn them out a bit?

 

You need to Re-Jet.
You need Pilot FUEL Jets capable of Metering more Fuel
It's likely that your Pilot Mixture Screws are wide-open right now and there isn't enough FUEL available to run the Bike smoothly at the SUPPLY LEVEL of the present Pilot FUEL Jets.

Likewise, the Main FUEL Jets.
It is possible that there is a hole in the Midrange or near Wide-Open-Throttles where the Main FUEL Jet cannot supply enough Fuel to meet the RPM's as they rise.

In this case EXPERIMENTATION is necessary.
Some alterations and experiments include:
Polished Diaphragm Piston Bores.
Enlargement of or adding another drilled air port at the base of the Piston.
Exchanging -or- alteration of the Outside Diameters of the Diaphragm Piston Needle Valve.
Enlargement of the Main AIR Jet to increase Main AIR feed capacity.
Precision Enlargement of the Inside Diameter of the four Emulsion Tubes by
.0015 -to- .0075 Allowing for a Faster reaction to the throttles being opened and an additional supply of Fuel -- BUT STILL REMAINING dependent on the Total amount of Main AIR Passing through the Emulsion Tubes.
Alteration of the Emulsion Tubes to supply more AIR and Fuel.
Adding an additional Port between existing Ports (O-o-O-o-O-o-O-o-O)
Increasing the Port Diameters Incrementally (1-o-2-o-3-o-4-o-5)

 

Well I'm glad I have that spare set of carbs then. I've had some medical expenses crop up recently which is why I haven't rebuilt them yet.

This is really all about my personal satisfaction with the performance of the bike. It pulls hard, right to the redline, it's not jerky when putt-ing through parking areas. The weak idle is my only point of dissatisfaction. I'm willing to rejet, but I'm not drilling out or enlarging any tubes because then, they're worthless to anyone else, especially anyone running a stock air box, or if I finally get an airbox and go through the hassle of removing my engine to get the bugger installed.

My valves are (just) in spec, the plugs look good. I'll try a sync again, and then look into buying larger jets. Thanks for the advice.

 

Well, the jets are cheap enough and easy enough to install so trying a few variations shouldn't cost too much. You could also try shimming the needles a bit with brass washers and see if that cures the lean condition. That'd be cheaper still.
thx,
baz

 

Pods or no pods, his bike should at least idle. He has carb problems!

 

Guys,
I was thinking about going with the pods also but let me see if I get this right. Say I like the "pod look" is it safe to say that it with some adjustments (rejetting/cleaning) that the bike will run just fine but I wont see any gains of performance with the pods? (no performance parts have been installed on my xj550)

 

That is a fair statement, the main problem is that "some adjustments" can go from a little tweak of the mixture to major rejetting, hairpulling and so on and so forth.

 

What you will have to cope with if you switch to Pods is compensating for a far larger amount of Intake Air than the Bikes stock arrangement is designed for.

See that Hole in the AirBox that alll the Intake Air passes through.
What passes through there is a Volume of Air rated in Cubic Feet Per Minute.
That entire Volume is shared by the four Carbs.

Un-restricting the Intake Air Flow means the Engine won't supply enough Fuel to handle all that extra air.
So, you have to find an arrangement of Jets that will.

Since the Main Jet and Emulsion Tube aren't capable of running that rich ... you spend the rest of your life tuning.

 

Hammer; "Just fine" is also subjective. The biggest issue is that CV carbs need a FINITE amount of air available to them to produce the correct velocities to function correctly. When faced with an "unlimited" air supply, they don't work well, especially at low velocity (such as idle.)

On a 550 you will almost certainly need to re-jet, and even with that done, you may still have problems balancing real-world rideability with a good idle. If you have a 550 with a stock exhaust system and solid airbox, I would think twice before cutting into it.

 

Im sure there has got to be a way to correct/fix this? or is that the question for the century lol.

 

when i first got my XJ650 RJ i put pods on straight away, got a mechanic to synch the carbs and richen them. bike ran great!

then, due to the dusty conditions i live around, and not wanting to buy four really expensive high quality pod filters, i returned to the stock box and filter.

after leaning the mixture to compensate, the bike runs great. either pods or box, there was no difference for me. many people state huge differences with either system. maybe experiment for a few days.

cheers.

 

When I bought my bike it had pods. I don't know how the bike ran before personally, but I know my brother did a lot of cursing because the stock airbox was falling apart. He spent all last spring rebuilding the carbs, jetting, rejetting and jetting some more and replacing the exhaust. In my opinion the bike runs great. Just sometimes it has a hiccup or two. It IS after all a 27 year old bike. The only reason my brother sold the bike to me is because he needed financing for his Maxim. I did have to take the bike to someone to have the carbs tuned properly. Which only put me out $50. Now that the enrichment circuit is clean the bike runs smooth and gives my uncle's Honda
Magna a run for it's money.