Topic: Why doesn't anyone make more restrictive Pods?

[Retro Rocket]

.it all comes down to how much you want to go thru to have them perfect

A lot of misconceptions in this thread, you will NEVER get them perfect on an old Honda, thats simply not the way they are designed actually, the majority of pods are poorly designed....

[TwoTired]

I don't know if this comment is in relation to pods only, or all bikes in general. But, yes, it does matter. These are not purely utilitarian vehicles for most, even those on this forum. Even for the 'average forum member'

Does it matter how good the bike looks if you put the average forum member on top of it?

Just wondering...

So, you are saying the bike's only value is as a fashion statement for most people on this forum? 

Interesting...

[dave500]

more resticted pods arent made because thats restricted.

[Geeto67]

I don't know if this comment is in relation to pods only, or all bikes in general. But, yes, it does matter. These are not purely utilitarian vehicles for most, even those on this forum. Even for the 'average forum member'

Does it matter how good the bike looks if you put the average forum member on top of it?

Just wondering...

So, you are saying the bike's only value is as a fashion statement for most people on this forum? 

Interesting...

no, he's calling us all ugly - 

anyway, - you want pods to work? spend real money porting the heads, then buy a set of CR carbs, then put any kind of filter on there you would like.

or.....build a plexiglass airbox.

[Psychonaut]

Compare a pod inlet (similar to #2) to the factory inlet (similar to #8) inside the airbox.

[MRieck]

Has anyone seen an oil painting with a pod filter as the focal centerpiece?  Perhaps if done in pastels?  I did a google image search for "pod filter art".  Lots of images.  None really artful or attractive, imo.  Anybody see a mobile made with pods?  Anyone here have pods hanging on the walls of their living room, 'cause they look so danged good?
Maybe if someone grafted a pod filter onto the nose on the Mona Lisa?  (Post apocalypse Lisa?)  Or, maybe twin pod filters on Madonna a bit below chin level?  Hey, thinking about it, maybe if the filters were shaped liked breasts, they could really enhance the visual appeal of the bike.   Think about it.  FOUR of them!

I don't get how anyone can think that the widely available pods look good. 
To me, they just look like a cheap afterthought someone was simply too lazy or dumb to properly engineer.

What evidence does anyone have that the stock air box is "restrictive"? ...and under what conditions.

Have any successful racers used a "pod"?  I thought they favored Velocity stacks.  Perhaps I wasn't paying attention.

Are race bikes made to be "pretty"?  I thought they were made to perform a specific function.  Go fast at max power.  Are there any motorcycle races that involve retrieval of groceries or other purchased consumables for human ingestion?

Do people really think of their bikes like accessory clothing.  Do pod filters really make your butt look smaller?  Maybe if you wrap your legs around smaller filters it makes your legs look beefier and more muscular?

Does it matter how good the bike looks if you put the average forum member on top of it?

Just wondering...

Yes....Team Obsolete on their Matchless that Dave Roper rides. '62 G50 MATCHLESS, Team Obsolete (Isle of Man)   Also on all the XR750's used in dirt tracking. I'm sure there are others as well.

[Lostboy Steve]

I think it comes from the mindset of automobile thinking...I had a Merkur XR4Ti Turbo, where getting cold air actually did make a difference...so I drilled a hole in the fender and plumbed a cold air cone to it...and the idea that carburetors are a distant memory to most...people dont remember them much less understand them...and as stock things relate to cars....it seemed back in the mid 70's any and all "stock" items could only be restrictive and performance robbing....not taking into account that a motorcycle  company like Honda would be veryvthorough about their intakes as relates to the special requirements of the bike applications. Additionally the regulations on bikes in respect to emissions were much less stringent...hence no thermactors or air recirculation pumps and so forth...this due to the small displacement and a bikes nature to be more recreational at least in the US, rather than everyday transport...still the ethic that any and all factory stuff must be a
performance hindrance still persists...and must be stripped...The "fashion" of performance takes many forms, a DTM wing on a Civic EX...which lowers top
speed...doesnt seem to matter...people just want the look...as long as magazines and
 marketing continue to push these flawed perceptions on the public...things like "pod
fever" will persist.

Seeing as how xr4ti's werent intercooled I could see how that would help. (BTW one of my favorite cars you should have kept it.)

[TwoTired]

Have any successful racers used a "pod"?  I thought they favored Velocity stacks.  Perhaps I wasn't paying attention.
Just wondering...

Yes....Team Obsolete on their Matchless that Dave Roper rides. Also on all the XR750's used in dirt tracking. I'm sure there are others as well.

Certainly makes sense that flogging about in the dirt would need a device for keeping it out of the engine.

I don't know much about the Matchless machines.   In the video, he mentions something about the carburetor, that I couldn't quite make out.  Is that a non-stock carburetor?  Maybe has no choice but to use a pod on dirty tracks with a non standard carb inlet size.

I went video surfing on you tube, where he takes it for a practice lap on Isle of Man.  Great fun watching that.
ISLE OF MAN, G50 Matchless LAP, Pt 1 of 2: "Race To The Sky." Team Obsolete
ISLE OF MAN, G50 Matchless LAP, Pt 2 of 2: "Duel In The Mountain!"...Team Obsolete .

Never did find out details of engine mods, carb mods, etc.

Oh well.

Cheers,

[Lostboy Steve]

I still say its less the lack of a velocity stack than it is the WHOLE airbox design that makes it more street-able. My buddy put ITB's on his 24v vr6 engine. He did it really nice where some where closer to the block than others (so the intake track length were all the same) Car Idled like hell but it was a monster otherwise. The whole idea of a plenum on vehicles (other than to produce enough vacuum for brakes and keep them quieter) is to make them tuneable for A/C, idle, cruising. To have a SMOOTH powerband. I had an rx-7 with a weber carb setup and other crazy #$%*. Unless you were screaming it between 10 and 13 grand it wasn't doing anything other than making noise. (Wish I had left it alone and eventually sold it for this reason.) All in all I am re-installing my airbox since I have it all and I'm tired of part throttle dips and idle hangs.

[lucky]

Quote:
"What evidence does anyone have that the stock air box is "restrictive"? ...and under what conditions."

The opening on the stock 1978 CB750 air box is 1 inch X 3.7 inches!

Please do not respond and say it is 3.68 X .932 inches.

[Lostboy Steve]

Quote:
"What evidence does anyone have that the stock air box is "restrictive"? ...and under what conditions."

The opening on the stock 1978 CB750 air box is 1 inch X 3.7 inches!

Please do not respond and say it is 3.68 X .932 inches.

Are you sure its not .931111119?  you asked for it... j/k

[TwoTired]

Quote:
"What evidence does anyone have that the stock air box is "restrictive"? ...and under what conditions."

The opening on the stock 1978 CB750 air box is 1 inch X 3.7 inches!

Please do not respond and say it is 3.68 X .932 inches.

Nice taking numbers in isolation.  ...without including any other relevant factors.  Ah, if life and science were that simple...
Do you only drive that air opening down the street/track without any other bits of bike attached?

What is the venturi area?

What is the exhaust outlet area?

Do you have any understanding about moving air through an orifice or duct?

Do you understand that you can move the exact same volume of air through any size orifice by changing the pressure differential across it?

Please do not respond with (I can't see any difference with very dark glasses on and using only one eye.)

Air is a gas.  You breathe a gas every day.  So, clearly any sort of gas is okay to breathe.  Is the this really the type of "logic" you wish to present?

Anyway, I asked for evidence.  Not a random observation.

[Geeto67]

Has anyone seen an oil painting with a pod filter as the focal centerpiece?  Perhaps if done in pastels?  I did a google image search for "pod filter art".  Lots of images.  None really artful or attractive, imo.  Anybody see a mobile made with pods?  Anyone here have pods hanging on the walls of their living room, 'cause they look so danged good?
Maybe if someone grafted a pod filter onto the nose on the Mona Lisa?  (Post apocalypse Lisa?)  Or, maybe twin pod filters on Madonna a bit below chin level?  Hey, thinking about it, maybe if the filters were shaped liked breasts, they could really enhance the visual appeal of the bike.   Think about it.  FOUR of them!

I don't get how anyone can think that the widely available pods look good. 
To me, they just look like a cheap afterthought someone was simply too lazy or dumb to properly engineer.

What evidence does anyone have that the stock air box is "restrictive"? ...and under what conditions.

Have any successful racers used a "pod"?  I thought they favored Velocity stacks.  Perhaps I wasn't paying attention.

Are race bikes made to be "pretty"?  I thought they were made to perform a specific function.  Go fast at max power.  Are there any motorcycle races that involve retrieval of groceries or other purchased consumables for human ingestion?

Do people really think of their bikes like accessory clothing.  Do pod filters really make your butt look smaller?  Maybe if you wrap your legs around smaller filters it makes your legs look beefier and more muscular?

Does it matter how good the bike looks if you put the average forum member on top of it?

Just wondering...

Yes....Team Obsolete on their Matchless that Dave Roper rides.  Also on all the XR750's used in dirt tracking. I'm sure there are others as well.

for the record we now use uni filter material around a velocity stack. At least that is what we used last year at Mid ohio on the XR909TT HD and the year before on rayborn's xr750, or the year before that on vesco/emde BSA A50R and IOM G50.

[MRieck]

Have any successful racers used a "pod"?  I thought they favored Velocity stacks.  Perhaps I wasn't paying attention.
Just wondering...

Yes....Team Obsolete on their Matchless that Dave Roper rides. Also on all the XR750's used in dirt tracking. I'm sure there are others as well.

Certainly makes sense that flogging about in the dirt would need a device for keeping it out of the engine.

I don't know much about the Matchless machines.   In the video, he mentions something about the carburetor, that I couldn't quite make out.  Is that a non-stock carburetor?  Maybe has no choice but to use a pod on dirty tracks with a non standard carb inlet size.

I went video surfing on you tube, where he takes it for a practice lap on Isle of Man.  Great fun watching that.
ISLE OF MAN, G50 Matchless LAP, Pt 1 of 2: "Race To The Sky." Team Obsolete
ISLE OF MAN, G50 Matchless LAP, Pt 2 of 2: "Duel In The Mountain!"...Team Obsolete .

Never did find out details of engine mods, carb mods, etc.

Oh well.

Cheers,

It is pretty standard. They run the "filters"....I absolutely hate the word "pods"...because they sucked something into the engine that cost them a win one year prior on Isle of Mann. Anyway....individual filters have their place....I just wish people would stop saying they don't.

[Retro Rocket]

I agree they have their place Mike but they just don't work as effectively as the airbox on the Honda's for the street with the stock carbs, plus they sound like they are trying to suck your balls out the leg of your pants and most lack the velocity stacks needed for the stock carbs to work effectively, the difference between tuning with the stock box compared to pod filters on stock carbed bikes is night and day...

[shorty24]

Not to digress, but just out of curiosity, what year are those Isle of Man clips from?

[TwoTired]

Not to digress, but just out of curiosity, what year are those Isle of Man clips from?

One of the comments in part 2 stated 1992.

[Mercutiojb]

Not at all! SOHC4 riders are the best looking around, naturally!

no, he's calling us all ugly - 

[Geeto67]

just to kind of steer this back on track and maybe refocus the OP's question into something more useful.......

ok, so we know that for ideal running on the street (in part throttle situations) we should have the carb rubbers and a plenum roughly about the same volume as the stock airbox. So, why doesn't someone make a much better looking airbox? or even better a more functional airbox?

look under the hood of any modern car and you will see all manner of dress up pieces for the plenum/intake. what's wrong with something similar for a motorcycle?

maybe a polished tube with two round filters at the end? or a case aluminum job with lots of fins?

I just don't think people are being creative enough in approaching this issue.

[Lil Red]

My side covers are beautiful...and probably way a total of 8oz. A piece...i dont think we are straying from the subject to far...which has become, when does form supercede function, should it? The point being you cant readily beat the airbox thats there...you could duplicate in chrome at which point the added weight would negate any real performance gain...in cars you can easily halve or double the horsepower as they are built to less of a performance standard by and large...plus the engine sits in a large protected area with all this room and it room can be further improved by power bulges and scoops etc...a sohc Honda like q 400f for instance already revs to 10 grand...pretty much has maxed out its valve area...it's breathing can only be pushed a little further...Above what? 12k rpm you begin to run into some serious metallurgy problems on the rods...and just keeping the thing together...at just 2000rpms higher than it comes from the factory...by comparison you can take a small block say Ford out of say a 80's LTD...that comes from the factory maxing out at 4700 rpm...get a cam, up the compression do the valves port the head put on headers open up the exhaust go from a 500 cfm carb to an 850 double pumper or even some exotic Inglese 4 x 45 dcoe Weber cross ram tarantula manifold and end up with something that turns 8200 rpmand has upped the bhp from 185 to 500+...its not so much that an airbox trumps pods...as much as the bike comes in an already very high state of tune and in a format that really doesnt allow for much growth either in horsepower or room for modifications. Sure that guy Yoshima put allot of hp out...but he had to go to Carillo to get them to make the smallest rods they had ever made..and a bunch of stuff like that...for the average tuner these bikes can get expensive to hot rod...the good thing is that they came pretty nicely set from the
factory...given the years they were manufactured

[754]

 My thoughts;
 Want pods more restrictive.. WET them..
 Everybody knows that KO airboxes flow the best..
 Nearly every bike at Bonneville uses K&N filters.. so yeah , racebike use them successfully.

 My first generation K&N seperate filters  seemed fine, would love to find another set.

 When the K&N rep was hanging out in our pit, I shoulda asked him about pods, I often wondered why they dont make the cylindrical VS the cone shaped anymore..

[Geeto67]

My side covers are beautiful...and probably way a total of 8oz. A piece...i dont think we are straying from the subject to far...which has become, when does form supercede function, should it? The point being you cant readily beat the airbox thats there...you could duplicate in chrome at which point the added weight would negate any real performance gain...in cars you can easily halve or double the horsepower as they are built to less of a performance standard by and large...plus the engine sits in a large protected area with all this room and it room can be further improved by power bulges and scoops etc...a sohc Honda like q 400f for instance already revs to 10 grand...pretty much has maxed out its valve area...it's breathing can only be pushed a little further...Above what? 12k rpm you begin to run into some serious metallurgy problems on the rods...and just keeping the thing together...at just 2000rpms higher than it comes from the factory...by comparison you can take a small block say Ford out of say a 80's LTD...that comes from the factory maxing out at 4700 rpm...get a cam, up the compression do the valves port the head put on headers open up the exhaust go from a 500 cfm carb to an 850 double pumper or even some exotic Inglese 4 x 45 dcoe Weber cross ram tarantula manifold and end up with something that turns 8200 rpmand has upped the bhp from 185 to 500+...its not so much that an airbox trumps pods...as much as the bike comes in an already very high state of tune and in a format that really doesnt allow for much growth either in horsepower or room for modifications. Sure that guy Yoshima put allot of hp out...but he had to go to Carillo to get them to make the smallest rods they had ever made..and a bunch of stuff like that...for the average tuner these bikes can get expensive to hot rod...the good thing is that they came pretty nicely set from the
factory...given the years they were manufactured

First off - you are assuming that in order to make something better you have to add something to it that will increase the weight and that is simply not the case. The airbox works because of some basic principles in airflow, it doesn't matter the container. And the plastic it is made out of is now 30-40 years old, kinda thick, and kinda heavy - there is def room for improvement in there if you look.

second of all - how to do make the jump from improving an airbox to rod failure? I think at this point you are just looking to argue for argument's sake.

I don't think it is an impossible dream to get an airbox that looks better than stock and works as good if not slightly better than stock. If you are willing to accept that as impossible that's your problem. just keep talking yourself out of it like there is no point.

[TwoTired]

Have any successful SOHC4 racers used a "pod"?  I thought they favored Velocity stacks.  Perhaps I wasn't paying attention.
Just wondering...

They run the "filters"....I absolutely hate the word "pods"

That's probably an important distinction.
If someone is looking for a functional solution to a carburetor inlet, they want a filtered system.
If someone is looking for a style change without regard to function, then they want a POD.

Since this is an SOHC4 forum, I assumed we would talk about those, rather than anything that had a "racer" moniker associated with it.
But, from what I have learned so far, the G50 has a single cylinder, single carburetor, single filter, 500cc engine revving to 7500 RPM.  I've no idea if the carb and intake velocities are comparable to what we see on the SOHC4 among the 4 carbs.  But, that seems unlikely, to me as I sit in my chair typing this.
As I watched the Isle of Man video of the G50 matchless, I made a few observations.  Before the start of the lap, I notice the rider had to constantly blip the throttle, presumably to keep the spark plugs clean. (This suggests the carbs were not tuned, or poorly tuned for a wide range of engine operation.)
During the lap, very seldom did the RPM dip below 6000 on a 7500 RPM red line engine.
This was no street bike.  For an example of a race bike that used a pod type filter, it might be beneficial to note these limitations and ask if you want those characteristics on your daily driver.

At Bonnevile, again these are are flat out machines where the operators care little about engine operation outside of a very limited operational rpm band. (They do care about ingesting salt crystals.)  So far, it seems the arguments all support using separate filters ONLY on specific purpose race machines where no other option is readily available.

Could the general populace be using individual filters to simply pose as a racer?

Regarding air boxes:
Anyone recall seeing air boxes on bikes before the SOHC4?  I'm wondering if these were early "cusp of a trend" design examples.

ok, so we know that for ideal running on the street (in part throttle situations) we should have the carb rubbers and a plenum roughly about the same volume as the stock airbox.

I'll speculate, that the SOHC4 design is non-ideal, but rather an early compromise design to fit within the confines and operational limitations of the bike then in production at that time.  I know the Cb550 Frame tubes directly interfere with that air plenum and the plenum was undoubtedly altered to fit.  It's not easy to find pods that fit there, either.  K&N doesn't even bother to make theirs fit.

So, why doesn't someone make a much better looking airbox? or even better a more functional airbox?

Because it is hard, requires knowledge outside of twisting a screwdriver and wrench, takes time and development money, the gains are in the 10% (or less) improvement margin, and doesn't fit within the "style wanna bees club" ideals.

I just don't think people are being creative enough in approaching this issue.

I agree.  But, if you ARE creative, and get it working well, then the club will just point, laugh, and criticizes however it looks, and tell you that cheap pods look better.  imo.

Cheers,

[TwoTired]

If we're talking mostly about looks, and forgetting for a moment any issues related to rain, crosswinds, etc... Why doesn't someone simply make a filter that 'looks' like a standard pod, but is more restrictive?  Roughly equally as restrictive as the stock box (per carb anyway)

It's about fluid dynamics.
Whatever you do to statically modify a "pod filter" applies linearly to a non linear demand of service.
Pods ONLY provide a "restriction" improvement over the stock system at very high RPM scenarios.   To do this, the intake duct is shortened, and the filter membrane type and area is changed, which lets in outside atmospheric pressure to the delivery side of the jets at all RPM selections (think jet change).  Further, the restrictive properties of both original and replacement systems are variable with air speed.  However, each system type presents a different rate of change across the air speed range.  The carburetor is calibrated to expect only the one (original) type and rate.

For a pod filter to be a drop in replacement, would require a mechanical linkage to the throttle in order to change its inlet size as the throttle is twisted.  This would "restriction match" the pod filter to approximate the profile of the stock system.   And such a feature is unlikely to "look" externally like the popular cheap pod that many revere as a symbol of inclusion into a desired "group".

Cheers,

[Geeto67]

As I watched the Isle of Man video of the G50 matchless, I made a few observations.  Before the start of the lap, I notice the rider had to constantly blip the throttle, presumably to keep the spark plugs clean. (This suggests the carbs were not tuned, or poorly tuned for a wide range of engine operation.)
During the lap, very seldom did the RPM dip below 6000 on a 7500 RPM red line engine.
This was no street bike.

Two,

The carbs are Amal GP carbs (IIRC, I haven't looked at them in a year) and are real pukka race carbs - no idle circuit. The rider has to keep blipping the throttle to keep it running because....well it is a race bike with race carbs. Dave has to blip the throttle down shifting because the bike is a 1940's designed 1962 manufactured large single (piston is larger than a Chevy piston at 5" across), and it doesn't benefit from modern things like a slipper clutch - if he wants to keep the back wheel from locking he has to match the rpms before he lets out the clutch. The plugs do load up at low RPM from time to time but that has a lot more to do with the heat range of the plug we run because the bike spends its life at redline.

I have no idea who tuned the G50 in 1992, but Roper does the setup on that bike every time it comes out now. It is a TT bike, not good for road races so it basically sees parade laps now. The closest it came to being run in anger was 3 years ago when roper and emde had a parade lap together at mid Ohio. Neither of them took it easy.


But back on track - the nice part about a plenum is volume is more important than shape. You can make it fit, it is why the airbox is the shape it is and not a perfect box.

Lots of morons buy pods because solely of the look. If you had something that looked as good but worked better that person could probably corner the a large part of the pod filter business. So there is incentive.