Who understands the PAIR system to know I can clamp it off, leaving it in place?

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The PAIR valve system should have nothing to do with the vacuum from the throttle bodies... if it's not maintaining speed, then you could have a split vacuum pipe, which is what happened to mine... easy fix just to replace the pipe... but as I said, the PAIR valve is a completely different circuit.... not much point in blocking it off unless you have after market pipes... I just use a kids marble and push it down the pipe that goes to the air box....


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The PAIR valve system should have nothing to do with the vacuum from the throttle bodies...
Okay, this is good news and I don't have to suck on the throttle body tube anymore. I obviously didn't die from it but it equates to watching a cat lick a puddle of gasoline.
Good news. It's not perfect but I clamped off the vacuum line between cylinder 2 and 4 to reduce the possibility of vacuum issue that I can't see and took it on a test ride.
Much improved over a maximum sustained speed of 55 miles an hour and held 70 for a while. Then it just gives up. Now I'm going to replace the VAC line from cylinder four to my new vacuum system from the cruise control install.
Is there any reason I can't just cap off the vacuum line at cylinder number 2? Once the original t-connector between two and four goes down above the engine I don't know if it's broken or split or what.
 
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At this time I would like to say that noticing the complete degradation of the VAC lines having been noticed sooner, to supply some actual vacuum while the engine is running is probably what would have led to a much more successful initial test ride. That's all I'm going to say about that.
 
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I have replaced the VAC lines at cylinder 2 and 4. I segregated cylinder number four to do the VAC for the cruise control, because I can't know the integrity of the VAC line at the other end from the cylinder 2 and 4 T connector. Will be able to test ride tomorrow.
 
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I have replaced the VAC lines at cylinder 2 and 4. I segregated cylinder number four to do the VAC for the cruise control, because I can't know the integrity of the VAC line at the other end from the cylinder 2 and 4 T connector. Will be able to test ride tomorrow.
It's a bit strange I think, because even if the vacuum lines were split and sucking in air, you would still be able run it at full speed, albeit a bit lean....
I would probably start looking at fuel pump... fuel pump issues have a tendency to cap off the speed or rpm, unnoticeable when in neutral... there are two tests for the fuel pump, fuel pressure and fuel flow.... I don't have the specs off hand, but worth checking both... if the fuel pressure is down, this means the motor is faulty, and is the flow is lacking, then the filters need replacing.... personally I've never had to remove the fuel pump on any ST, but to me, this is where your problem starts.... if I understand your original post...


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At this time I would like to say that noticing the complete degradation of the VAC lines having been noticed sooner, to supply some actual vacuum while the engine is running is probably what would have led to a much more successful initial test ride. That's all I'm going to say about that.
My vacuum lines to the cruise control diaphragm were all hardened and split fro heat over the years... but it never stopped the bike from revving right out.... if I understand you correctly, the bike refuses to go above 55mph ??


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My vacuum lines to the cruise control diaphragm were all hardened and split fro heat over the years... but it never stopped the bike from revving right out.... if I understand you correctly, the bike refuses to go above 55mph ??


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Today's test ride revealed it wasn't willing to hold at any speed for longer than 5 to 10 seconds even though I improved the connections with vac lines. So it's a little disconcerting to hear that even with you're bad vacuum lines that it performed.
Not having taken a screwdriver with me on the first test ride I came back and opened the access to the dip switches and set number four from off to on. That was in hopes of it not lurching so hard when I pressed the set button on the cruise control remote that it would just give up after trying to initially set. What it does seem to do is not lurch so hard for the second test ride but it shuts off immediately.
It's frustrating because it seems so close for it to just work properly it's worse than it not trying to set it all.

The next attempt since my pulley has no ratio for leverage to work the throttle and I believe it to be a very hard pull. Something those of you who have drilled and tapped bolts on the bell housing automatically prove there is less work for the servo to do. My hope is, making the effort to extend an arm off of my pulley, to make use of what cable pull the servo has to do will lessen its load and not make it too quick to give up. Those are the symptoms I'm able to articulate at the moment.
 
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The bikes inability to get past 55mph, suggests that either the servo is defective or installation problems. I think the install manual called for some slack in the servo cable at the bikes throttle cable connection when the bike's not running-too much slack there? Check the servo travel length compaired ti to the bikes throttle travel length ( should be the same or bike's length slightly longer). Another question, what are you using as a speed signal from the bike to the cc?. Dropping out as you described suggests , to me, that the rear light is the problem-try cutting and capping both ends of the servo wire that connects to the hot side of the stop light, If it then holds.. you,ve found that problem. And for the sake of simplicity- forget about the pair connection and tee into the vacume line at the fuel shut off valve. Once it's working you can then play with adult. vacume sources.
 
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Here is the best view of the modification I will be modifying. As you can see from the servo there is a direct ratio pull around the pulley to the throttle. The arm, with any luck we'll have an extension to it to aid in a relief the work the servo has to do.
IMG_20170521_175409.jpg
 

John OoSTerhuis

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FWIW - In normal operation, e.g. the Audiovox CC engaged and holding 65mph, the throttle grip can be rotated and held to increase speed for a bit (to creep forward out of a cage's blind spot, for example) and then gently released, whereby the bike will slow back to 65mph and continue to hold that speed.

You either have too much total resistance in the servo cable routing which the CC senses and shuts itself off, OR in your setup/install the servo cable is already fully retracted and simply can't achieve the set engine rpm (ignition pulse). IOW, the throttle bellcrank or linkage (wherever you've attached the end of the servo cable) can't rotate further to the position needed-for/relative-to/associated-with the engine rpm at the time you pushed the Set button. In your case, anything faster than the rpm associated with 55mph in 5th gear.

Note what the rpm is for, say 70mph, in 5th gear. Then slow down, put the ST in 4th gear and run it up to the same rpm, engage the Audiovox and see if it holds...

STill thinking out loud here...

John
 
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Honestly, Moody , I can't make out what's going on in that picture. Yes I am wearing my glasses too.
I have connected the cruise control cable to the throttle link that moves the other side of the carburetor. Fred Adkins attached his cruise control here. It was a move to install the cruise control without having to pull the carbs.
 
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FWIW - In normal operation, e.g. the Audiovox CC engaged and holding 65mph, the throttle grip can be rotated and held to increase speed for a bit (to creep forward out of a cage's blind spot, for example) and then gently released, whereby the bike will slow back to 65mph and continue to hold that speed.

You either have too much total resistance in the servo cable routing which the CC senses and shuts itself off, OR in your setup/install the servo cable is already fully retracted and simply can't achieve the set engine rpm (ignition pulse). IOW, the throttle bellcrank or linkage (wherever you've attached the end of the servo cable) can't rotate further to the position needed-for/relative-to/associated-with the engine rpm at the time you pushed the Set button. In your case, anything faster than the rpm associated with 55mph in 5th gear.

Note what the rpm is for, say 70mph, in 5th gear. Then slow down, put the ST in 4th gear and run it up to the same rpm, engage the Audiovox and see if it holds...

STill thinking out loud here...

John
I always appreciate the input, I could be missing something.
1. In an effort to allow for a higher rate of vacuum with higher engine rpm's, I have ruled this out attempting to set the cruise in 4th gear, still releases early.
2. When originally locating the servo, I mounted it with the most cable pull with only 1 bead of slack.

During test rides, I have enough plastic off to glance at how hard it pulls to initially set. It appears abrupt enough for sensors to not attempt to maintain speed. So far I have been bending mounts and am drilling the pulley to accommodate the new pull mechanism.
 
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5 hours later I have modified a new bracket. Hopefully the expert eyeballing and the cinching of these brackets proves to be a better experience.
Throttle fully closed.
IMG_20170526_160615.jpg

Throttle fully open, the whole length of the servo cable.
IMG_20170526_160635.jpg
 
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It isn't working in the worst way possible. It doesn't just not work. It sets, when I press the set button. The small amount of slack is taken up and tension is provided to the throttle, it holds between 2 and 25 seconds, then fails, as if I squeezed the brake or clutch, or the servo pulled the cable to the end of it's ability (which by the way, isn't even close).
There isn't anything else I can think of. The wire connections are very good, but it leads me to believe there is a signal it's receiving somewhere to cause it to disengage.
There isn't anymore road testing that can be done for the moment. I can check over the connections but there aren't that many, other than looking for an obvious crossed wire. We'll see. It's making me think Rostra, an electric option.
Oh well, this kind of thing has happened before. It's so close, just not consistent.
 
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It isn't working in the worst way possible. It doesn't just not work. It sets, when I press the set button. The small amount of slack is taken up and tension is provided to the throttle, it holds between 2 and 25 seconds, then fails, as if I squeezed the brake or clutch, or the servo pulled the cable to the end of it's ability (which by the way, isn't even close).
There isn't anything else I can think of. The wire connections are very good, but it leads me to believe there is a signal it's receiving somewhere to cause it to disengage.
There isn't anymore road testing that can be done for the moment. I can check over the connections but there aren't that many, other than looking for an obvious crossed wire. We'll see. It's making me think Rostra, an electric option.
Oh well, this kind of thing has happened before. It's so close, just not consistent.
When I first bought my bike some 10 years ago, it did the same thing... I found the manufacturer of the unit wasn't that far from me, and they upgraded the switch housing and did some other upgrades as well... they had oscilloscopes and all sorts of test units... my cruise control would also stay locked in for 10 or so seconds then cut out...


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When I first bought my bike some 10 years ago, it did the same thing... I found the manufacturer of the unit wasn't that far from me, and they upgraded the switch housing and did some other upgrades as well... they had oscilloscopes and all sorts of test units... my cruise control would also stay locked in for 10 or so seconds then cut out...


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Understood. When I went after my wired connections I noticed the ground from the servo had paint before the metal and though attempts were made to clear the paint and make an actual ground, warranting another test ride, it will just not hold longer than a couple of minutes. It was an improvement for the length of time that it would hold but somewhere after I press set or resume it just gives up.
There seems to be good vacuum, there is a strong pull for the portions that it does work. The dip switch settings are one is on, 2 through 6 is off and seven is on. This is the way a lot of the ST1100's are set up the way I've been able to tell.
So after about 20 hours of wrestling with this thing it looks like I'm going to be defeated unless I were to have another hand control or servo I could test with. Don't know what else I can do.
 
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In all of this, because the tupperware was off, I discovered a fuel leak at the vacuum valve before the carbs..but that's another thread.
 

John OoSTerhuis

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That's certainly a unique idea with the pulley, but....

I don't know how well Fred's install method worked, or if you duplicated it exactly but yours isn't working, sadly. These are the only installs that I know of over all these years that do not use an attachment point on the throttle bellcrank. In an attempt to not have to pop up the back end of the carbs. My recommendation is to use this install which many others have used successfully:
http://www.st-riders.net/coppermine/thumbnails.php?album=33

If you do give up, I'll be happy to take your Audiovox off your hands. Or ride over here and we'll get'r done together.

John
 
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