Hi all, I am new to the forum, and motorcycles overall. I decided to poke around my bike today, just to get a feel, and decided to clean my air filters. I ended up having to pull the entire gas tank to get at the filters on a 1985 fj1100. Is that normal, I am I simply overlooking something? It seems like a real hassle, and not knowing what I was doing, I ended up dumping a bunch of fuel all over :wacko3: I won't do that again, but still.
Quote from: ryanschoebel on July 31, 2017, 06:14:39 PM
Hi all, I... decided to clean my air filters. I ended up having to pull the entire gas tank to get at the filters on a 1985 fj1100. Is that normal, I am I simply overlooking something? It seems like a real hassle...
No, it's not normal. You should've only needed to remove the seat, one side panel, and the three Philips screws that hold on the access cover for the filter. Don't worry about your wasted efforts though. They're not really wasted, because you're just familiarizing yourself with the bike. Things like that happen to a lot of us.
If you don't have one already, you should look into getting a genuine Yamaha Service Manual. They're worth the price. You can find them used for a decent buck on eBay from time to time.
Quote from: FJ1100mjk on July 31, 2017, 07:52:56 PM
Quote from: ryanschoebel on July 31, 2017, 06:14:39 PM
Hi all, I... decided to clean my air filters. I ended up having to pull the entire gas tank to get at the filters on a 1985 fj1100. Is that normal, I am I simply overlooking something? It seems like a real hassle...
No, it's not normal. You should've only needed to remove the seat, one side panel, and the three Philips screws that hold on the access cover for the filter. Don't worry about your wasted efforts though. They're not really wasted, because you're just familiarizing yourself with the bike. Things like that happen to a lot of us.
If you don't have one already, you should look into getting a genuine Yamaha Service Manual. They're worth the price. You can find them used for a decent buck on eBay from time to time.
The way that you phrase it, it sounds like you expect one filter? on my bike, i have 4 smaller, individual filters. I assume one for each carb? And i do have a manual, somewhat. A Forum guy by the name of Red emailed me a copy last night, but i havent done anything but skim it yet. I do appreciate him doing it though, as im sure it will come in handy.
Quote from: ryanschoebel on July 31, 2017, 09:32:51 PMQuote from: FJ1100mjk on July 31, 2017, 07:52:56 PM
Quote from: ryanschoebel on July 31, 2017, 06:14:39 PMHi all, I... decided to clean my air filters. I ended up having to pull the entire gas tank to get at the filters on a 1985 fj1100. Is that normal, I am I simply overlooking something? It seems like a real hassle...
No, it's not normal. You should've only needed to remove the seat, one side panel, and the three Philips screws that hold on the access cover for the filter.
The way that you phrase it, it sounds like you expect one filter? on my bike, i have 4 smaller, individual filters. I assume one for each carb? And i do have a manual, somewhat. A Forum guy by the name of Red emailed me a copy last night, but i havent done anything but skim it yet. I do appreciate him doing it though, as im sure it will come in handy.
Ryan,
You have an "upgrade" in the air filter department. This set-up would not be in the manuals, but somebody here may have paperwork for their own installation, which should help with yours. Without seeing what you have there, I'm guessing that what you did was about right. Look at the cone-type or the K&N air filters from RPM, and if either one is the same as yours, Randy at RPM may be able to supply any tech data or installation sheets that might be needed.
Quote from: red on August 01, 2017, 12:56:53 AM
....You have an "upgrade" in the air filter department.....
I have many names for those fucking filters and "upgrade" is not one of them. :mad:
Throw them away. Throw them far away. Put them in a trash barrel and light them on fire.
Get a pair of these: http://rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod (http://rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod)
At least they manage to stay on your carbs and actually filter.
Quote from: Pat Conlon on August 01, 2017, 01:14:11 AM
Quote from: red on August 01, 2017, 12:56:53 AM
....You have an "upgrade" in the air filter department.....
I have many names for those fucking filters and "upgrade" is not one of them. :mad:
Throw them away. Throw them far away. Put them in a trash barrel and light them on fire.
Get a pair of these: http://rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod (http://rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod)
At least they manage to stay on your carbs and actually filter.
hahaha, sounds good :sarcastic: Would these be better than trying to revert to whatever the original set up was?
Does the tank have to be removed to service Randy's(RPM) Dual Filters. Thanks
Good question. Are UniPods better than the oem filter box?
Some say no, some say yes.
There are many of us (myself included) who have the Uni's and swear we will never go back to the oem air box.
Yes, we have to remove the seat and both side covers and (at a minimum) lift the tank (block of wood under the back of the tank) or remove the tank to remove the UniPod filters for servicing vs as Marty said above, you only need to remove the seat and side cover to get to the oem filter.
Where the Uni's shine is when it come time to r/r the carbs for cleaning. (It's not a matter of if, but when)
The Uni's make this task far easier than struggling with the air box.
You sure gain a lot of room under the seat area with the oem airbox removed.
There has never been an issue for me riding in a heavy rain with the UniPods.
There can be a slight performance benefit in using Uni's along with an aftermarket free flowing header and ignition advance.
There is little performance benefit just using UniPods by themselves. (although I do love the growl)
The air velocity passing thru your CV carbs will increase with Uni's, meaning that your needle will be in a slightly lower position in the needle jet, so it is recommended to shim your needles. http://www.fjowners.com/index.php?topic=4714.0 (http://www.fjowners.com/index.php?topic=4714.0)
If you are doing all three engine mods, UniPods, Exhaust and ignition advance, along with the needle shims, it is recommended to rejet your carbs, and up the size of your pilot jets (from 37.5 to 40 or 42.5) and up the size of your main jets.
You may want to do this rejetting anyway (regardless of the mods) the USA FJ's are set lean from Yamaha to begin with..
I'm sure others will chime in on the importance of retaining the oem airbox. I have heard these opinions before but I am not convinced.
Cheers Pat
Quote from: vegetta58 on August 01, 2017, 04:03:48 PM
Does the tank have to be removed to service Randy's(RPM) Dual Filters. Thanks
From what i understand, yes and no. As pat said, you can lift the tank, not necessarily remove it. However, if im right, the only set up that doesnt require lifting/removing the tank is the original OEM airbox. That is designed so that you dont need to.
Quote from: Pat Conlon on August 01, 2017, 04:15:14 PM
Good question. Are UniPods better than the oem filter box?
Some say no, some say yes.
There are many of us (myself included) who have the Uni's and swear we will never go back to the oem air box.
Yes, we have to remove the seat and both side covers and (at a minimum) lift the tank (block of wood under the back of the tank) or remove the tank to remove the UniPod filters for servicing vs as Marty said above, you only need to remove the seat and side cover to get to the oem filter.
Where the Uni's shine is when it come time to r/r the carbs for cleaning. (It's not a matter of if, but when)
The Uni's make this task far easier than struggling with the air box.
You sure gain a lot of room under the seat area with the oem airbox removed.
There has never been an issue for me riding in a heavy rain with the UniPods.
There can be a slight performance benefit in using Uni's along with an aftermarket free flowing header and ignition advance.
There is little performance benefit just using UniPods by themselves. (although I do love the growl)
The air velocity passing thru your CV carbs will increase with Uni's, meaning that your needle will be in a slightly lower position in the needle jet, so it is recommended to shim your needles. http://www.fjowners.com/index.php?topic=4714.0 (http://www.fjowners.com/index.php?topic=4714.0)
If you are doing all three engine mods, UniPods, Exhaust and ignition advance, along with the needle shims, it is recommended to rejet your carbs, and up the size of your pilot jets (from 37.5 to 40 or 42.5) and up the size of your main jets.
You may want to do this rejetting anyway (regardless of the mods) the USA FJ's are set lean from Yamaha to begin with..
I'm sure others will chime in on the importance of retaining the oem airbox. I have heard these opinions before but I am not convinced.
Cheers Pat
Hey Pat, Im confused, and not only because i only understood about half of that haha. (sorry, still learning!) Are the uni pods what i have? I thought you didnt like those? (that is of course me assuming uni pods is referring to one pod or filter for each intake?) and as for resetting my jets, i dont know too much about motorcycle engines, but i can tell just from smell, my engine smells very rich upon idle, during, and after warm up. Im gonna go ahead and do some research to try and better understand everything you mentioned before, but as always, i really appreciate all the help and answers so far!
Yea, sorry....I see your confusion. I call the RPM foam filters UniPod filters. I'm refering to the Dual pod foam filters made by Uni sold by RPM.
The individual pod filters (of which you have 4) have filtering issues and (by the nature of their design) the #1 or #4 filter is snug against the perimeter frame rail. What happens is, under load, the torque causes the engine to move in the frame which knocks those filters off the carbs. Many a FJ'er has found those filters laying on the top of the engine case after long rides.
So....They don't filter well when they manage to stay on, and they sure as hell don't filter well laying on the top of your engine case.
The RPM Uni dual pod foam filters have no clearance issues, they stay put, and being a 2 stage foam filter design, they actually do a good job filtering.
Quote from: Pat Conlon on August 01, 2017, 05:23:48 PM
Yea, sorry....I see your confusion. I call the RPM foam filters UniPod filters. I'm refering to the Dual pod foam filters made by Uni sold by RPM.
The individual pod filters (of which you have 4) have filtering issues and (by the nature of their design) the #1 or #4 filter is snug against the perimeter frame rail. What happens is, under load, the torque causes the engine to move in the frame which knocks those filters off the carbs. Many a FJ'er has found those filters laying on the top of the engine case after long rides.
So....They don't filter well when they manage to stay on, and they sure as hell don't filter well laying on the top of your engine case.
The RPM Uni dual pod foam filters have no clearance issues, they stay put, and being a 2 stage foam filter design, they actually do a good job filtering.
Gotcha, that makes more sense! I will place an order for a pair this evening, and put them on once they arrive. However, when i put them on, i should shim the needles? Is that relatively hard to do?
Quote from: ryanschoebel on August 01, 2017, 05:03:40 PMAre the uni pods what i have? I thought you didnt like those? (that is of course me assuming uni pods is referring to one pod or filter for each intake?) and as for resetting my jets, i dont know too much about motorcycle engines, but i can tell just from smell, my engine smells very rich upon idle, during, and after warm up. Im gonna go ahead and do some research to try and better understand everything you mentioned before, but as always, i really appreciate all the help and answers so far!
Ryan,
Most likely, you have one of these three items, for air filters:
http://rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod (http://rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod)
http://rpmracingca.com/proddetail.asp?prod=Carb%3ARC-0984&cat=39 (http://rpmracingca.com/proddetail.asp?prod=Carb%3ARC-0984&cat=39)
http://rpmracingca.com/proddetail.asp?prod=Carb%3AConeFilter&cat=39 (http://rpmracingca.com/proddetail.asp?prod=Carb%3AConeFilter&cat=39)
Which one do you have there?
If you have been through the Owners Manual, then you know where the choke control is located, and how it works. If the exhaust smells rich, make sure that the choke control is fully OFF when riding, and that the choke controls on the carbs are going fully OFF as well. You should be able to watch the choke controls on the carbs respond to the choke lever (ring) on the handlebars. After you see how the carb chokes work, try to push the chokes on the carbs more fully OFF by hand, and if you can, then you need to clean and lube the choke cable (or just replace that cable). Lubricate all of the choke linkages, also. There is a gadget made for getting lube into a cable, which also needs a needle-spray can of petroleum lube (NOT WD-40!) with the skinny red straw. Wal-Mart and lots of MC shops sell these cable-lube gadgets.
https://www.amazon.com/Motion-Pro-08-0182-Cable-Luber/dp/B0012TYX9W (https://www.amazon.com/Motion-Pro-08-0182-Cable-Luber/dp/B0012TYX9W)
If the chokes all work as intended and the exhaust smells rich, maybe the air filters are somewhat dirty (clogged), or you may need some expert help in cleaning, adjusting, or re-jetting the carbs. Don't be in a rush to re-jet the carbs though; the problem is often very much simpler. Add SeaFoam to the gas tank just before you fill it (following the directions), before you have
anything mechanical done. Every auto parts store sells SeaFoam. A tank or two of treated gasoline can fix a lot of problems. Yamaha shops may balk at the carb work (maybe because they have little or no experience), but a good independent MC mechanic shop can probably do it right.
Keep in touch. :good2:
Quote from: Pat Conlon on August 01, 2017, 04:15:14 PM
The air velocity passing thru your CV carbs will increase DECREASE with Uni's, meaning that your needle will be in a slightly lower position in the needle jet, so it is recommended to shim your needles. http://www.fjowners.com/index.php?topic=4714.0 (http://www.fjowners.com/index.php?topic=4714.0)
Pat, fixed it for you. Easy to get confused on this subject
Quote from: red on August 01, 2017, 06:01:19 PM
Quote from: ryanschoebel on August 01, 2017, 05:03:40 PMAre the uni pods what i have? I thought you didnt like those? (that is of course me assuming uni pods is referring to one pod or filter for each intake?) and as for resetting my jets, i dont know too much about motorcycle engines, but i can tell just from smell, my engine smells very rich upon idle, during, and after warm up. Im gonna go ahead and do some research to try and better understand everything you mentioned before, but as always, i really appreciate all the help and answers so far!
Ryan,
Most likely, you have one of these three items, for air filters:
http://rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod (http://rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod)
http://rpmracingca.com/proddetail.asp?prod=Carb%3ARC-0984&cat=39 (http://rpmracingca.com/proddetail.asp?prod=Carb%3ARC-0984&cat=39)
http://rpmracingca.com/proddetail.asp?prod=Carb%3AConeFilter&cat=39 (http://rpmracingca.com/proddetail.asp?prod=Carb%3AConeFilter&cat=39)
Which one do you have there?
If you have been through the Owners Manual, then you know where the choke control is located, and how it works. If the exhaust smells rich, make sure that the choke control is fully OFF when riding, and that the choke controls on the carbs are going fully OFF as well. You should be able to watch the choke controls on the carbs respond to the choke lever (ring) on the handlebars. After you see how the carb chokes work, try to push the chokes on the carbs more fully OFF by hand, and if you can, then you need to clean and lube the choke cable (or just replace that cable). Lubricate all of the choke linkages, also. There is a gadget made for getting lube into a cable, which also needs a needle-spray can of petroleum lube (NOT WD-40!) with the skinny red straw. Wal-Mart and lots of MC shops sell these cable-lube gadgets.
https://www.amazon.com/Motion-Pro-08-0182-Cable-Luber/dp/B0012TYX9W (https://www.amazon.com/Motion-Pro-08-0182-Cable-Luber/dp/B0012TYX9W)
If the chokes all work as intended and the exhaust smells rich, maybe the air filters are somewhat dirty (clogged), or you may need some expert help in cleaning, adjusting, or re-jetting the carbs. Don't be in a rush to re-jet the carbs though; the problem is often very much simpler. Add SeaFoam to the gas tank just before you fill it (following the directions), before you have anything mechanical done. Every auto parts store sells SeaFoam. A tank or two of treated gasoline can fix a lot of problems. Yamaha shops may balk at the carb work (maybe because they have little or no experience), but a good independent MC mechanic shop can probably do it right.
Keep in touch. :good2:
Hey Red, I have exactly the third one. I do know about the choke, and it operates as it supposed to . I only use it to start and warm up, and then completely shut it off when riding. Thankfully, i do know what seafoam is at least! :yahoo: I have worked on engines before, but never carb engines. Only fuel injected unfortunately. I did clean the air filters yesterday (after dumping fuel all over them taking off the tank :dash2:) ill try the seafoam as well, and see if that helps the rich idle.
IMHO here are more aspects mixed together. :crazy:
If you have K&N filters, you need just phillips head screwdriver long enough to reach clamps on inner ones and remove.
You have to remove tank, at least it makes thinks way easier, but as ´85 has vacuum operated petcock, there should be minimal if any fuel leakage.
If your petcock does not close, this can be one of the reasons you run rich.
K&N filters are made from wire mesh and cotton vs. Uni pods (or those twins aka bi pods ) are made of foam.
For maintenance of both, you have to clean them and spray with light oil provided with filters.
Huge difference is what will happen later.
If you do not maintain UNI, as it is made from foam, more and more dust will clog pores in foam and filter is more and more restrictive for air and bike runs too rich, but no mess can pass to carbs.
If you do not take care of K&N and similar cotton filters, (they are even less restrictive, you can see through) being more and more restrictive for air will reach a point, that vacuum in your carbs will be strong enough to suck dust into your carbs as it will be stronger than adhesive force of oil.
OK, restrictive.... hmm, if you run constant speed, does not matter on filter, according to engine displacement and RPM, you need certain amount of air/fuel mixture.
Less restrictive filter is, lower vacuum is at the carb filter side. But less vacuum means less fuel sucked into mixture, that is why open filters runs lean.
If you quickly open throttle, vacuum lowers so acceleration pumps were added to enrich mixture.
Filter does not affect speed of air as those are constant velocity carbs, just changes vacuum rate.
How can cone filters increase HP works easy.
Part of the engine power is utilized to make fresh AF mixture flow into cylinders.
Lower vacuum is on intake, lower power needed to waste on this.
Higher RPM means more air that needs to pass filter, more difference can be noticed. (approx 0,000001 HP at WOT) :lol:
This is why turbos/chargers are used to help engine breath, polishing intake mainfolds etc.
Another thing is that OEM filter box reduces air spin, so coming to carb, air has constant speed and can be mixed with fuel properly.
Those cone filters make turbulences and AF ratio is not homogeneous.
That can be fixed with velocity stacks, their length matters, but in most of motorbikes, there is not enough space for that.
And last, before you do anything else, just see colour of spark plugs, that shows a lot :yes:
Quote from: FJ_Hooligan on August 01, 2017, 06:14:12 PM
Quote from: Pat Conlon on August 01, 2017, 04:15:14 PM
The air velocity passing thru your CV carbs will increase DECREASE with Uni's, meaning that your needle will be in a slightly lower position in the needle jet, so it is recommended to shim your needles. http://www.fjowners.com/index.php?topic=4714.0 (http://www.fjowners.com/index.php?topic=4714.0)
Pat, fixed it for you. Easy to get confused on this subject
Yeppers, thanks David! You've been teaching us about this for years now.....one of these days I'll get it right
Quote from: ryanschoebel on August 01, 2017, 06:19:16 PMHey Red, I do know about the choke, and it operates as it supposed to . I only use it to start and warm up, and then completely shut it off when riding. . . . ill try the seafoam as well, and see if that helps the rich idle.
Ryan,
Great! See if the simple stuff does any good, first. If
only the idle is too rich, that may be a fairly simple (cheap) screwdriver adjustment. The carb floats may also be set wrong, so I'd recommend using a good MC shop, for the right fix. Not every MC shop has an Exhaust Gas Analyzer, but that would be the first-class ticket for any carb work.
Quote from: Bezmozek on August 01, 2017, 07:37:09 PM
You have to remove tank, at least it makes thinks way easier, but as ´85 has vacuum operated petcock, there should be minimal if any fuel leakage.
If your petcock does not close, this can be one of the reasons you run rich.
Hey Bezmozek, you are right, it is a vaccum open petcock. I, however, didnt know that at the time, and turned the fuel cutoff switch to what i believed was off. Turned out, i turned it to prime, and so it just let the fuel pour out in a stream :pardon: my bad haha.
Quote from: Bezmozek on August 01, 2017, 07:37:09 PM
OK, restrictive.... hmm, if you run constant speed, does not matter on filter, according to engine displacement and RPM, you need certain amount of air/fuel mixture.
Less restrictive filter is, lower vacuum is at the carb filter side. But less vacuum means less fuel sucked into mixture, that is why open filters runs lean.
If you quickly open throttle, vacuum lowers so acceleration pumps were added to enrich mixture.
Filter does not affect speed of air as those are constant velocity carbs, just changes vacuum rate.
How can cone filters increase HP works easy.
Part of the engine power is utilized to make fresh AF mixture flow into cylinders.
Lower vacuum is on intake, lower power needed to waste on this.
A lot of what you're saying is mostly correct but it's a little more complicated. I do agree that the K&N filter is a bad filter design.
A less restrictive filter flows air slower through the carb compared to the stock filter and airbox. A CV carb uses the velocity of the airflow to create the vacuum signal that pulls fuel through the jets. Air flowing at a lower velocity has a smaller vacuum signal. However, a CV carb responds to this lower vacuum signal by dropping the vacuum slide which reduces the carb throat area. The smaller venturi area speeds the air velocity back up to the desired (Constant) value which reestablishes the correct vacuum through the carb.
So, the proper vacuum signal is restored BUT, the vacuum slide is now at a lower level (compared to its position with a stock filter) which means the slide needle is now at a lower (LEANER) position in the needle jet. That's why the mixture is leaner.
If you open the throttle quickly on a CV carb, the intake vacuum measured at the sync port will drop, but the air velocity through the carb actually spikes momentarily which provides a fuel delivery spike until the vacuum slide reacts to raise the slide and slow the air back down. Motorcycles (stock) do not have accelerator pumps.
A less restrictive air filter design does affect the speed of the air, with a CV carb the slide needle needs to be shimmed higher to flow more fuel and compensate for the lower vacuum of the slower air.
Class dismissed.
Quote from: FJ_Hooligan on August 01, 2017, 10:13:10 PM
A less restrictive filter flows air slower through the carb compared to the stock filter and airbox. A CV carb uses the velocity of the airflow to create the vacuum signal that pulls fuel through the jets. Air flowing at a lower velocity has a smaller vacuum signal. However, a CV carb responds to this lower vacuum signal by dropping the vacuum slide which reduces the carb throat area. The smaller venturi area speeds the air velocity back up to the desired (Constant) value which reestablishes the correct vacuum through the carb.
So, the proper vacuum signal is restored BUT, the vacuum slide is now at a lower level (compared to its position with a stock filter) which means the slide needle is now at a lower (LEANER) position in the needle jet. That's why the mixture is leaner....
...Class dismissed.
No, please, class still in session haha, Im still trying to understand :shout:. So, based on what you are saying, if the filters were changed out from the stock filters, but the carbs never adjusted or rejetted accordingly, that could cause it to run rich? or am i understanding that wrong?
EDIT nope, thats wrong. ignore me
Quote from: Pat Conlon on August 01, 2017, 05:23:48 PM
Many a FJ'er has found those filters laying on the top of the engine case after long rides.
So....They don't filter well when they manage to stay on, and they sure as hell don't filter well laying on the top of your engine case.
Now I don't mean to say that you're right,( :hi:) but I was riding around today, and I went over a fairly solid bump. I heard a knock, and lo and behold, look what I found....
Quote from: FJ_Hooligan on August 01, 2017, 10:13:10 PM
A lot of what you're saying is mostly correct but it's a little more complicated. ...
Yes it is, I think we are saying same, but in different ways.
But it is not possible to have slower or faster flow depending on filter.
Still you have to feed 4 cylinders of your engine with A/F mixture, so if you have OEM filter, with same carb settings, butterfly valve position etc, does not matter on speed of air, you need 1097 cm3 of mixture to feed FJ 1100.
If you change to Uni/K&N as you say air will flow slower, but than you do not have enough A/F mixture to run your engine.
As Bernoulli says, faster the air goes through carb, lower pressure it has.
But bike carb does not use air speed to operate. It is all about pressure, via diaphragm raise/lover needle according to differences between pressures.
But with moving just needle, in different RPM will change the speed of air, so that is why throttle slide is changing throat diameter to keep constant velocity.
While changing to hi-flow filter, you are changing vacuum level at the intake, which means one side of equation :flag_of_truce:
Quote from: Bezmozek on August 01, 2017, 11:19:37 PM
Yes it is, I think we are saying same, but in different ways.
But it is not possible to have slower or faster flow depending on filter.
Still you have to feed 4 cylinders of your engine with A/F mixture, so if you have OEM filter, with same carb settings, butterfly valve position etc, does not matter on speed of air, you need 1097 cm3 of mixture to feed FJ 1100.
If you change to Uni/K&N as you say air will flow slower, but than you do not have enough A/F mixture to run your engine.
As Bernoulli says, faster the air goes through carb, lower pressure it has.
But bike carb does not use air speed to operate. It is all about pressure, via diaphragm raise/lover needle according to differences between pressures.
But with moving just needle, in different RPM will change the speed of air, so that is why throttle slide is changing throat diameter to keep constant velocity.
While changing to hi-flow filter, you are changing vacuum level at the intake, which means one side of equation :flag_of_truce:
No, we are not saying the same thing.
With a CV carb, it's not the AMOUNT of air it's the VELOCITY of the air. Yes, the intake stroke is filling the volume of the cylinders with an air/fuel mixture but it's sensitive to the rate of airflow and not simply the amount of air.
Bernoulli says the FASTER the air flows through the carb the HIGHER the vacuum.
A CV carb is all about the speed of the air and NOT the quantity. Yes, the position of the slide is dependent on the vacuum, but that vacuum is created by the airflow velocity
If you don't understand that then you don't understand CV carbs
Read the link that Pat provided.
I can see that we're having a language translation problem. Sorry about that.
You say Bernoulli says the faster the air goes through the carb, the lower pressure is has.
We are agreed!