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

Ok, I don't know where to begin, I did a lot of things that weren't planned, they just became good ideas as I went. Once the tank was removed I explored the linkage for freedom of movement, alignment for the pull on the throttle from the servo and it's slack.
There was too much slack. Not that it shouldn't have worked, but the importance of the right amount of slack may not have been adjusted perfectly. Here's why. If there is too much slack at throttle rest, the first thing that happens when you're in 5th gear at 3k rpm, will be even more slack because you've slightly twisted the throttle for this speed. This I took notice of and made sure, before assembling everything again, there was a gnats wing of slack in the linkage of throttle and servo. To be sure I've conveyed this properly, once the throttle is all the way relaxed, the length of the servo cable is at it's most relaxed, so there is the most room for it to capture the speed and throttle up big long hills without disconnecting, something I've waited for to happen so far.
So, basically by taking up the initial slack, there is a lot less the servo has to work for adjusting speed going down the road.
The next most astounding thing that happened is, I decided with the tank removed to connect a vac gauge to a test port in my vac system for cruise. Running the engine before the tank went back in, if I found out there was a vacuum issue would take a lot more time to get it apart again.
20 inHg at 3k rpm. I couldn't believe it. All tests before were in the 10 to 12 range. I don't know where it came from but being connected to cylinder 3 has given me a lot more confidence that it won't be a vac supply issue and shouldn't have to make a larger vac container. When I shut the engine off the gauge showed no leak in the system 5 to 10 minutes later. Won't go on a test ride for 3 more hours.

No dice. Couldn't keep it engaged. It's even worse trying to engage then before I started. I can turn it on, set it, then it disconnects. I wonder if it's a fault in the buttons? At this point trying anything other than what I've done would be refreshing.

A theory for the possibility the buttons aren't working properly in the controller is not being able to think of anything else. The red blinking light under the cap in the servo when the engine is running blinks so that tells me the connection to the coil is able to count the number of times it's firing. Controller turns on so there's power going to it. The symptom of it capturing the speed when I press set then disengages is like the solenoid is stuck for being able to hold a vacuum that it lets in.

On the way home with an hour long ride and nothing better to do than ride safe, I just kept pressing on set to see if some exercise would get it to work. It didn't. At this point I could ground the purple wire that cancels cruise when apply the brakes but this hasn't proved to keep cruise engaged any longer with trying something else.

Taking a chance in writing Murph's Kits, since I didn't buy this directly from them, I wanted to see if they offered any advice or support even though their website is up front about figure it out, and it's probably not the solenoid. He offered a lot of what has been mentioned before in this thread and to be careful grounding the purple wire as depressing the brakes won't disconnect the cruise, though squeezing the clutch would due to sensing a higher rpm without acceleration.
So, since I removed the possibility of there being a vacuum leak, I will make sure the purple wire is well grounded before further testing.

Time for an update. Per recommendation from Blayde, who has helped with several emails back and forth, like I continue to get help from this thread, suggested I try servo switch one and two on. This would raise the count on the tach in case it was disconnecting at 60mph due to having servo 1 and 7 on, 2-6 off. I did this reluctantly as so many other ST1100 riders have it set 1 and 7 on and 2-6 off and it works.
I noticed the minimum speed it will set changed. I can begin trying to set it around 55 to 60mph. I would trade this higher speed if it actually worked consistently. I doesn't stay on. It will for about 30 seconds. I can even feel it accelerate going up slight hills so I know the servo isn't maxing out, then it just cuts off. I can reengage but it will cut out soon after. I haven't checked the rest of the connections yet, but did want to let you know I hadn't given up yet. The next test will involve a vac gauge to observe while riding. This will ensure I have above the minimum required, 6 inHg, for the servo to function.

Took off the tupperware and changed dip switches back to what everyone seems to use, 1 and 7 on, 2 - 6 off.
I hooked up a tube for a vac gauge while cruise is engaged to monitor the condition of the vac system during operation.
While the engine was running I noticed I'm pulling 20 inHg. When I shut the engine off the vac held and 20 minutes later it was 18 inHg. Obviously there is a leak somewhere, but not significant enough to disengage cruise while the engine is running and vac is being constantly produced.
Another observation while the purple wire was connected to the "brakes on" wire, I was reading 167mv. For those of you who don't know it's very close to an 1/8th of a volt positive. When the brake light circuit comes on the purple wire from cruise control senses this voltage and disconnects the cruise control until you resume or reset on the control pad.
I don't know how much voltage being sensed in this wire will disconnect cruise, so in the mean time I have reconnected the purple wire to my battery to insure the best ground for my next test and the voltage measures 1.8mv, a dramatic difference from the much higher voltage when it was connected to the positive brake wire. So, I'm probably destined for placing a relay to ground to rule out cruise disconnecting due to sensing too much voltage before I apply brakes. Even though I don't have LED brake lights but it's better to prevent it from disconnecting.
This is it. It's the last series of tests I can do before I replace the servo. Fortunately it's only 80.00 for the servo only. What I needed to do, with the help of a lot of people, namely John Oosterhuis, was go over every thing that can prevent cruise from working properly. Servo cable bind, enough vacuum in the system, the proper amount of slack in the cable, the right number of beads on the servo cable and of course being properly wired. I don't know when I'll get a chance to test drive, but when I do, it will be the last one. There isn't anything else I can try a different way. Once I placed the the servo exactly how it's been done on previous installations that worked, I have to be that small percentage of a servo that just won't work.
Will let you know what happens of course.

Final test was today, failed. I had connected the purple wire to the battery ground to rule out cruise control disconnecting because it sensed voltage coming through the "brake lights on" wire. Would not stay engaged. What kept me trying so long is cruise stays engaged at 35 to 50 mph. Not going faster. So I was perplexed with why that was, maybe it was a vacuum issue. Maybe it was a wiring issue. I've wired before, many times. So when you follow someone else with where and how they wired it, it should just work, well...
I ordered another servo, 84.00 taxes and shipping. If it works, great, then it wasn't something I did. If it doesn't, I'll have my wiring to inspect very closely. It was a good exercise in patience. Hopefully I've had enough exercise.

I installed the new servo. I was debating posting anything at all, but over 150 posts in this thread, a lot of people may be rooting for this to work after such a long haul. We are beyond fingers crossed at this point, there have been so many tests.
Servo switches 1 and 7 on, the rest are off. I probably spent the most time with cable and throttle adjustment. Since tank removal is involved for the best access to this link while adjusting where the servo cable is in relationship to the throttle at rest I didn't mind taking my time. Had I thought of it, I would have taken a picture after the 2nd servo was installed. In short, the servo cable is fully extended, with a tiny bit of slack, while the throttle is completely at rest and in contact with the idle adjustment screw.
I think that's really all that's worth mentioning at this point, I will be able to test it tomorrow. At least knowing full well the vacuum won't be an issue.

First test around 25mph does it even engage, yes. This is promising, in means the initial installation of the new servo is making good mechanical and electrical connections.
Out of town, setting it at 50mph has an initial surge as it is attempting to set, then immediate release. Aside from every symptom the new servo is giving me that the last one did, I still have to disconnect the servo's purple wire from the "brake lights on" connection and ground it, to make sure the 160mv in the circuit before I press the brakes isn't what is automatically disconnecting it. (I really hope that is the problem)
I tried this test with the previous servo connected, but it continued to disconnect after trying to set cruise, between 5 seconds and 2 minutes leaving me to believe, at long last with so many tests, it might be time to rule out the servo.
I know there are some who have the relay to ground on the bike installed whether they had LED brake lights or found the servo was disconnecting because too much voltage in the "brake lights on wire". Once they installed the relay, all was well.
What I find interesting is the "brake lights on" wire has any voltage at all before the brakes are applied, 160mv. When I ground the servo's purple wire, there is 1.8mv present, next to nothing, so hopefully that takes care of that.
Lastly, since we're talking all about voltages. The wire from the servo that needs power all the time has over 13 volts when the engine is running, so that should be enough. The ground connections in both cases of the servo and the wire harness have had the paint removed so the connection is metal to metal. Will keep you informed, of course.

5 hours later, I left my destination I'd test ridden the servo the first time. I am positive it stayed engaged at low speed, as it has before, but I could not repeat my low speed test again, as it would not stay engaged.
Not expecting that inconsistency to happen doesn't matter, I already had a plan when I knew it wouldn't stay engaged for more than an initial pull before it disengaged at 50mph. So, I have grounded the purple wire and we key on and voltmeter at the purple wire connection it reads 0.0 volts. So that would prevent it from disconnecting due to no voltage being read at this wire, I will obviously pay attention that a "brake lights on" signal will not be disconnecting the servo. Til another time I can test ride. My next plan, should cruise not stay engaged, go through the trouble shooting guide to make sure voltage is present at each of the phases of connections and brake lights on and ignition on.

Rode again today. Expected it to be better than initially engaging then disconnecting immediately. I was surprised it wasn't a little different by grounding the purple wire. So, sticking to the plan of going over the troubleshooting guide for making sure all of the tests check out is what's on the menu next.

The joke is on me this time, I should have checked what I was grounding the purple wire to, when ruling out too much voltage in the "brake lights on" wire, for it not staying engaged on the first test. I clipped it to the aluminum frame the foot pegs are mounted to. It's not so much it was a bad idea, but you electrical enthusiasts know that if you've chosen a location for grounding something, to actually make sure it is metal that closes a circuit, not a big piece of metal that doesn't.
I get that, in haste, for making this change, to ground the purple wire, with my new servo was supposed to be very close for successfully heading down the road with cruise control is why I forgot to test for a good ground.
It's no wonder the cruise wouldn't engage at all (frustratingly) but unbeknownst to me wasn't properly grounded. But, I it's not the only thing I came here to tell you.

Since the last test, I already had doing a full electrical test by the book (the section in the back of the book that tells you what the voltage values are supposed to be with ignition on and pressing certain buttons).
The red LED lighting up with every push of a button and while the engine was running and the hand control was turned on, the successively faster flashing LED (under the servo connection cover with 2 screws) as the engine rpm's go up. All checked out. Every test. With a new servo, a properly grounded (this time) purple wire. There is no other reason I can think of this won't work. I have had an enormous amount of help, this forum and Blayde, a contact from Murphskits.com, to get me to this point.

I'm confident it will at least engage. When I was done finding an appropriate ground I started the engine, revved up to about 3k rpm, turned on the servo at the hand control and pressed set.
It will attempt to engage, pulling on the throttle at the servo cable connection but quickly disconnect as it senses too many rpms compared to speed traveled. This told me two things. The purple wire is now properly grounded to engage the servo and vacuum is present to pull on the servo cable. The next test ride should be the one. I should be jammin down the road with a cruise control system that stays engaged. Could be until Wednesday for this next ride.

I finally decided to take a few pictures of my install. John O will likely recognize a lot of similarities, because quite honestly, when I was running into functionality problems with my idea, I needed to model it after someone's who has worked for years.
This youtube video shows the successively faster beat to the LED as the rpm's increase. This is the idea that it is properly sensing the ground wire connection of the coil, as the servo make the necessary adjustment for holding the throttle at the preset adjustment.
No need to have your volume set high for this one
https://www.youtube.com/watch?v=s91Y1v3Q5r4

This shows the effort in removing the paint to make the ground connection near the servo. Ground was checked for continuity at this connections to the ground cable on the battery.


This connection is the ground location under the airbox cover for the remote connection.


This is an attempt to show the servo cable to throttle cable connection. I followed John's technique for this because you're drilling through your frame's cross-member and I preferred to only make one hole. After the throttle is at rest, the servo is completely extended
with a little slack, enough to allow the throttle to rest on the idle adjustment screw, as it should.


This monstrosity you're looking at is having removed the wire's insulation of one of the two blue wires with a yellow strip, tinning and soldering a connection, complete with shrink tubing, to be able to plug the blue wire that senses the coil's ground.


Before I chose another grounding point for the purple wire, believing there to be too much voltage sensed in the "brake lights on" wire, this serves as a bad example. I wouldn't have had a failed test had I grounded the purple wire and tested it to make sure it was grounding. This plate would be a good grounding source if there wasn't so much rubber dampening.

Will not stay engaged. It's worse than the first servo. At least it would stay engaged longer than 2 seconds some if the time.
Without it being a vacuum supply issue and a new servo. It has to be electrical. Don't know what to do next. Been a long haul.

Did I misunderstand?... with the throttle bellcrank resting on the stop at idle, the servo pull cable should be extended. When the CC is engaged to hold the throttle rotated to a higher rpm the cable will withdraw into its sheath by the servo.

Edit: if you finally give up, how much do you want for the servos, old and or new. Mine is getting sluggish and I can just plug yours in and then tear my old one apart later to inspect/fix if I get around to it.

John OoSTerhuis said:

Did I misunderstand?... with the throttle bellcrank resting on the stop at idle, the servo pull cable should be extended. When the CC is engaged to hold the throttle rotated to a higher rpm the cable will withdraw into its sheath by the servo.

Click to expand...

Yes you are correct. Throttle bell crank on the stop at idle and servo cable is totally extended. Knowing the way the servo works by vacuum, the cable would need to be out the most, to allow the travel for pulling on the throttle cable for acceleration.

Edit: if you finally give up, how much do you want for the servos, old and or new. Mine is getting sluggish and I can just plug yours in and then tear my old one apart later to inspect/fix if I get around to it.

Click to expand...

I haven't given up yet. In fact, I thought today I would even trade having cruise control if I understood why it didn't work. I have ridden plenty of miles without it, seized the opportunity to buy one for 40.00, just have never been able to get it to stay engaged. I really need to find out why it doesn't work. Today's test, after I grounded the purple wire, it should have worked. I'll obviously have to check for vacuum again, but I'm running out of ideas. There isn't any reason I couldn't send you the older servo, if it works, great.

Miracles do happen. No, it's not fixed yet, but there's no way I wouldn't tell you I had an offer for someone who has not only done his own install, has offered to come to place to help me out. John, I know you offered to do this too, I just couldn't provide housing and didn't feel compelled to cheer the effort you'd make to come out here to help drive this home without being able to return the favor. Tomorrow at 9A, the adventure continues...

What will happen out of this, because of my experience, is throw some more logs on the fire to help with troubleshooting in the future, should someone want to have a cruise control for 180.00.

Blayde showed up around 9A as promised, I had the tupperware off to get right to work, no delay. He would ask questions about what each connection was and where, and I had answers. At first he thought it might be that I had LED brake lights, but they are in conjunction with an incandescent brake light circuit, so it is grounded as it should be. Besides, the purple brake light sensing wire has been disconnected and grounded this whole time because I couldn't keep cruise engaged for longer than 2 seconds. So the consideration that it might be sensing too much voltage in the "brake lights on" wire is what the step in grounding the purple wire was for.

We went on several test rides, trying a different hand control, making sure the dip switches were set properly. He has helped 100 people with this install and this one seems to be taking the cake. Why? Because what a common error is LED brake lights don't ground, so it's not a good source for making that connection. He expressed a couple times, he thought it would be about 15 minutes of deductive work and 2hrs and 15 minutes later, still no cruise.

All tests check out.
The LED blinks successively faster as the rpm's go up.
The LED flashes with each press of "Set" and "Resume".
All of the wires that are supposed to have no voltage or 12+ volts when buttons are pressed have 12+ volts.

I get that it doesn't work still, but with Blayde perplexed means there is an underlying issue somewhere that is beating him at this game too.

Right now, a suggestion is to try engaging the cruise at much higher rpm, maybe 2nd gear at 5 to 6k. This will allow the servo to pull more cable in and manage speed at that setting compared to 3 to 4k. The throttle does not move that much to maintain 3500 to 4k rpm, so it's possible it has something to do with that.

Another thing is the trajectory of the connection made from the servo. I know some of you have installed the servo connection here and thought to line up the pull at the bell housing like this.


A thought, is to lower bracket holding the servo cable and make more of an approach like this.


Again, with everything checking out, with a person who probably has the most experience putting this on bikes and helping people in the nation, isn't getting the cruise to stay engage longer than 1 or 2 seconds. It's a worse experience than the servo I had previously because at least it was stay engage longer and at a faster speed. I don't know what it's going to take to get this to work, til the next time..

I have another legitimate update. Because at this point, if it's not worth talking about it isn't going to be. These photos represent a discovery in a vac tubing anomaly.


What you're looking at is a notch on in the inside of the vac tubing. This is not the same picture. I had two different tubing connections like this. My theory is, with being able to maintain close to 20inHg during it's operation that the damaged tubing played a role in it not wanting to stay engaged for long. I don't fully understand how, but it's the only thing I can blame at the moment. I have run the engine after replacing the vac tubing and will check on it again soon.