Air cut valves...again

[FLAVALK]

After installing the Redeye carb kit and following the air cut valve vacuum check procedure, I found two valves that appear to have a bad diaphragm (won’t hold vacuum). I see where this topic has been discussed somewhat but have not found if anyone has defeated the valve by plugging the valve nipple and the brass nipple (vacuum source) at he bottom of the carb. This option is mentioned in the following online post.

https://www.motorcycleproject.com/text/aircut_valve_more.html


So, has anyone done this, and if so, what was the result?

[Mooskee]

In the process of rebuilding a couple of sets of carbs, I too have found 2 bad air cut valves. I tried taking them apart to see if repairs were possible, but see no obvious way to do it. I had a set of carbs that have a busted carb body and used two of the air cut valves off of it. The New air cut valves are $73 plus
shipping! I read the article you posted, but the links to the white paper do not work for me. I am interested to know what you find out about disabling the ACVs. I think as time goes by many of us will be asking that question. I know some people will say they have never found a bad one, but I have found 2 bad ones. One on each of 2 sets of carbs. If you take a broken one apart you will wonder how it lasted this long, and why the heck it cost $73.

[FLAVALK]

In the process of rebuilding a couple of sets of carbs, I too have found 2 bad air cut valves. I tried taking them apart to see if repairs were possible, but see no obvious way to do it. I had a set of carbs that have a busted carb body and used two of the air cut valves off of it. The New air cut valves are $73 plus
shipping! I read the article you posted, but the links to the white paper do not work for me. I am interested to know what you find out about disabling the ACVs. I think as time goes by many of us will be asking that question. I know some people will say they have never found a bad one, but I have found 2 bad ones. One on each of 2 sets of carbs. If you take a broken one apart you will wonder how it lasted this long, and why the heck it cost $73.

The cost of these things is ridiculous. There’s no telling how long mine have been bad and I’m very tempted just to cap them and see what happens. Maybe the popping on deceleration won’t be too bad.

[98valk]

flexible rubber paper cement.

[FLAVALK]

flexible rubber paper cement.

For what, to seal the nipples?

[98valk]

flexible rubber paper cement.

For what, to seal the nipples?

if cracked diaphragm will seal and still function. used it on a slide diaphragm yrs ago on another honda, never had a problem after the repair.

[FLAVALK]

flexible rubber paper cement.

For what, to seal the nipples?

if cracked diaphragm will seal and still function. used it on a slide diaphragm yrs ago on another honda, never had a problem after the repair.

Unfortunately, these ACV’s are one piece so getting to the diaphragm is not possible. I would have to destroy the unit to get to the diaphragm.

[Mooskee]

Unfortunately, these ACV’s are one piece so getting to the diaphragm is not possible. I would have to destroy the unit to get to the diaphragm.

They will separate at the top where the vacuum hose connects. As I stated before I haven't had any luck getting one to work after putting it back together. I will have to try the rubber cement.

[Warlock]

published instructions for defeating the air cut valve for DOHC 750

[Warlock]

This is what I did to bypass the air shutoff valve. Got me 12 vacuum caps 1/8" and installed them in the place where the short tube connects from the vacuum on the carb to the air shutoff valve. Seems to have cured my popping real bad when I crank it up. Made me realize I had some bad shut off valves. Will have to re sank my carbs again. What some people don't realize, me either at that time, the carb cleaner or what ever you use to clean the carbs without removing the air valves will destroy the little diaphragm in the shut off valve. Not going to spend that money to replace them. So in the future be careful when cleaning the carbs without removing the air shutoff valve. Lesson learned.
David

[FLAVALK]

This is what I did to bypass the air shutoff valve. Got me 12 vacuum caps 1/8" and installed them in the place where the short tube connects from the vacuum on the carb to the air shutoff valve. Seems to have cured my popping real bad when I crank it up. Made me realize I had some bad shut off valves. Will have to re sank my carbs again. What some people don't realize, me either at that time, the carb cleaner or what ever you use to clean the carbs without removing the air valves will destroy the little diaphragm in the shut off valve. Not going to spend that money to replace them. So in the future be careful when cleaning the carbs without removing the air shutoff valve. Lesson learned.
David

I removed the air jet (brass tube in the ACV) and filled it with RTV and reinstalled it. I then took the vacuum hose that runs from the plastic nipple of the ACV to the brass nipple in the lower carb body and shoved a .22 caliber pellet inside effectively “capping” the two. We shall see in a few days how that works. Waiting on float valves to complete the carb rebuild. I have a LOT of balls in the air right now with this makeover. New master cylinders all around, new fork seals, complete carb overhaul, new brakes all around, new brake caliper rebuild all around, new tires. Hell, it’s gonna be a new bike! 

[Jersey]

This is very interesting read and concept.  Of those have done this, what is your experience in how the bike runs?

I wouldn't have a problem with the decel popping, as long as that's all that's occurring.

What about gas mileage, power, etc.? 

[FLAVALK]

This is very interesting read and concept.  Of those have done this, what is your experience in how the bike runs?

I wouldn't have a problem with the decel popping, as long as that's all that's occurring.

What about gas mileage, power, etc.? 

From what I’ve read and researched, which is a lot, the only downside seems to be some popping on hard deceleration. Two of the six cards on my bike have been plugged. I will give feedback after I get the carbs back in the bike and go for a ride which should be (hopefully) next weekend. Still waiting on some parts to finish the job.

[Bigwolf]

Yes, I deleted my cut valves with just 25,000 miles on my bike.  I found 5 of the 6 would not hold vacuum.  The air cut valves are there for only one reason.  That is to enrich the mixture during heavy decel conditions and by doing so reduce the decel popping in the exhaust.  It does nothing to improve the running of the engine!

I have now put another 40,000 miles on my bike with no undesirable results ...... although some decel popping which does not concern me.

[agrady1995]

FLAVALK;


Tried to DM you. Let me know if you see it, or DM ME.


Kilroy.

[FLAVALK]

Yes, I deleted my cut valves with just 25,000 miles on my bike.  I found 5 of the 6 would not hold vacuum.  The air cut valves are there for only one reason.  That is to enrich the mixture during heavy decel conditions and by doing so reduce the decel popping in the exhaust.  It does nothing to improve the running of the engine!

I have now put another 40,000 miles on my bike with no undesirable results ...... although some decel popping which does not concern me.

Good to know...thanks

[John Schmidt]

Yes, I deleted my cut valves with just 25,000 miles on my bike.  I found 5 of the 6 would not hold vacuum.  The air cut valves are there for only one reason.  That is to enrich the mixture during heavy decel conditions and by doing so reduce the decel popping in the exhaust.  It does nothing to improve the running of the engine!

I have now put another 40,000 miles on my bike with no undesirable results ...... although some decel popping which does not concern me.

Jerry, what needed to be plugged and how did you do it. I have my rebuilt carbs out in the process of moving them from the old bike to the trike. I know a couple aren't functional so have been debating doing what you did...just removing those before installing the carbs.

[Bigwolf]

Yes, I deleted my cut valves with just 25,000 miles on my bike.  I found 5 of the 6 would not hold vacuum.  The air cut valves are there for only one reason.  That is to enrich the mixture during heavy decel conditions and by doing so reduce the decel popping in the exhaust.  It does nothing to improve the running of the engine!

I have now put another 40,000 miles on my bike with no undesirable results ...... although some decel popping which does not concern me.

Jerry, what needed to be plugged and how did you do it. I have my rebuilt carbs out in the process of moving them from the old bike to the trike. I know a couple aren't functional so have been debating doing what you did...just removing those before installing the carbs.

John,
The only thing needed to defeat the air cut valve is to block the vacuum that operates it.  That little short piece of tubing from the carb base up to the valve, when blocked, stops the operation of the valve.  That is all you have to do.  I found a bb or air soft pellet worked perfectly.  I put the bb in the hose close to the carb base.  Do not block the holes where the valve seats in the carb body!  If you close those passages, your idle circuit will not function correctly.  Leaving the old valve there will ensure that the idle air circuit gets the air it needs to function correctly.

[Bigwolf]

I removed the air jet (brass tube in the ACV) and filled it with RTV and reinstalled it.

Flavalk,
You will be better off to remove that rtv before you get everything back together.  If you leave that  rtv in there, the idle circuit will not be getting air properly.

[John Schmidt]

Thanks Jerry, I'll go swipe some from my son-in-law. 

[turtle254]

[/quote]

John,
The only thing needed to defeat the air cut valve is to block the vacuum that operates it.  That little short piece of tubing from the carb base up to the valve, when blocked, stops the operation of the valve.  That is all you have to do.  I found a bb or air soft pellet worked perfectly.  I put the bb in the hose close to the carb base.  Do not block the holes where the valve seats in the carb body!  If you close those passages, your idle circuit will not function correctly.  Leaving the old valve there will ensure that the idle air circuit gets the air it needs to function correctly.
[/quote]
I would think that all you need to plug is the side off the carb. , and not worry about leaving the connection on the acv just open? That would be easiest way to do it.

[FLAVALK]

I removed the air jet (brass tube in the ACV) and filled it with RTV and reinstalled it.

Flavalk,
You will be better off to remove that rtv before you get everything back together.  If you leave that  rtv in there, the idle circuit will not be getting air properly.

Will do, thanks.

[Bigwolf]

I would think that all you need to plug is the side off the carb. , and not worry about leaving the connection on the acv just open? That would be easiest way to do it.

If you plug the holes in the side of the carb body where the acv is mounted, the air cannot flow thru there!  The air needs to come out one of those holes and go in the other hole for proper idle circuit operation.  The acv completes that circuit when it is not getting vacuum from the rubber hose.  If you block that circuit by plugging those holes, you force the idle circuit to assume enrichened decel mode all of the time.  Also, the air the idle circuit gets this way will not go thru the diffuser as it should to help vaporization at idle and low speed.

Not sure what you mean by “leaving the connection on the acv just open”.  The rubber tubing needs to be on there!  It just needs to be plugged if you are disabling the acv.

[turtle254]

nd low speed.

Not sure what you mean by “leaving the connection on the acv just open”.  The rubber tubing needs to be on there!  It just needs to be plugged if you are disabling the acv.


[/quote]Just take the tubing off and plug the conn on carb with cap, then just leave the other end on the acv open (dont do anything on that conn)

[Jersey]

I would think that all you need to plug is the side off the carb. , and not worry about leaving the connection on the acv just open? That would be easiest way to do it.

If you plug the holes in the side of the carb body where the acv is mounted, the air cannot flow thru there!  The air needs to come out one of those holes and go in the other hole for proper idle circuit operation.  The acv completes that circuit when it is not getting vacuum from the rubber hose.  If you block that circuit by plugging those holes, you force the idle circuit to assume enrichened decel mode all of the time.  Also, the air the idle circuit gets this way will not go thru the diffuser as it should to help vaporization at idle and low speed.

Not sure what you mean by “leaving the connection on the acv just open”.  The rubber tubing needs to be on there!  It just needs to be plugged if you are disabling the acv.

BigWolf... pardon if this an obvious question. Just want to be clear on what you're suggesting.  

To do this correctly, are you saying to only block the Vacuum circuit of the ACV?

[John Schmidt]

Let's see if I have this right; pull off one end of the short hose, plug that hose, then put the hose back in place and I'm done?!? I have the carbs ready to go on the trike after removing them from the old bike so i want to do this before installing them.

[turtle254]

Let's see if I have this right; pull off one end of the short hose, plug that hose, then put the hose back in place and I'm done?!? I have the carbs ready to go on the trike after removing them from the old bike so i want to do this before installing them.

Just plug the conn. on the carb. and leave the conn. on acv open ... just pull the vac. line off,
Plug carb. Simple

[Bigwolf]

Let's see if I have this right; pull off one end of the short hose, plug that hose, then put the hose back in place and I'm done?!? I have the carbs ready to go on the trike after removing them from the old bike so i want to do this before installing them.

That is correct.

[John Schmidt]

Thanks Jerry, by 8:00pm today I should be a few steps closer to completion of the transfers. Still will need to pull the fairing to expose the wiring. Have to adapt the wiring from the Tourer to the I/S, have an oversize diameter set of bars with the wiring running inside and want to use them on the trike along with the risers. I'll be installing the I/S bars on the Tourer along with the wiring involved. Will be an interesting(?) exercise on both bikes. Once that's accomplished I'm pretty much done and will be able to move the old bike to my son-in-law's company garage, thereby affording me more space in mine and his is heated.  

Completed blocking all the tubes in the ACV circuit. That was not the most enjoyable evening I've ever spent since the carbs were all together. It can be done at that stage but I suggest taking a tranquilizer before hand. One side is rather easy to gain access...forget which. The other side...believe the right, was a royal PITA. Four were NG so I just did all six and called it good, used some pellets for my SIL's air gun he uses to keep the muskrat population down. They live on a rather large pond which they own and is surrounded by houses. Interestingly, it happens to be an old Oneida Nation federal wildlife reserve so no developer can come in and build around it and dump runoff in the pond. But the muskrats will ruin the ponds edge and undermine up into various yards in the area so Andy pops them off when he sees them. I digressed a bit...tomorrow I mount the carbs in the trike, then will remove the fairing to the degree it takes to expose the wiring for the handlebar controls. Next will be swapping handlebars and when I do I plan to remove the entire front brake system as a unit with the bars at the same time since I overhauled the front calipers about 18 mo. ago. Once I get to that point, that will be the last step in getting the Trike up to par...at least for now. 

[98valk]

minks catching those muskrats

https://www.youtube.com/watch?v=qeo5moeV254

[gordonv]

minks catching those muskrats

https://www.youtube.com/watch?v=qeo5moeV254[/url

I like Josephs video, so I went back to his first posts and watched them all in order, so he would get the credits/$ for them. I like watching the dogs going after rats too, and using the mink to flush out the rats for the dogs.

[98valk]

minks catching those muskrats

https://www.youtube.com/watch?v=qeo5moeV254[/url

I like Josephs video, so I went back to his first posts and watched them all in order, so he would get the credits/$ for them. I like watching the dogs going after rats too, and using the mink to flush out the rats for the dogs.

they are amazing.    There is one video where some peta a%%holes, broke onto his property and released all of his minks.    see the vids of the Red mink, he said best he ever had, it was one of the ones released.

[gordonv]

they are amazing.    There is one video where some peta a%%holes, broke onto his property and released all of his minks.    see the vids of the Red mink, he said best he ever had, it was one of the ones released.

I don't think he ever said, in youtube, who broke in to his property, and he didn't know if they where taken or released, but that's why he moved and got the new dog (the previous one was hit by a car) which he trained as a guard dog for his family protection. Nice video in the training too on that breed.

Yes, that one mink and the one he lost when he didn't have it on a leash and a biker startled it into the woods.

I first started watching the Brits using their Terriers for rating on farms. Something to see. Joseph should also put up a barrier when he starts flushing, he would get less lost rats.

He should get a motorcycle to carry the mink around on. A trunk for the mink cage.  now it's on topic (sorry).