Cruise Control

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As a long distance touring machine, the ST1100 holds it own very well. However, to make several hours a day in the saddle just a bit more comfortable, as well as to help guard against speed creeping up due unbridled exuberance, an electronic cruise control is a popular add-on (farkle). I had this on my wish list for some time and finally got around to installing one.

Here are some details of how I installed mine.


Throttle Interface:

One of the trickiest things about this installation is interfacing the throttle with the cruise control cable. Since it's a "universal kit" and not even really intended for motorcycle use, the potential is endless. Never the less, after careful study of several other published accounts of installing this same cruise control I ended up with my own novel, and I think simple but very effective approach.

The throttle "arm" is the kit supplied item, cut shorter from the top end. It is attached to the bell crank by drilling a small hole into the end of the brass carb shaft (brass is soft so very easy to drill, I used a dremel with a tiny bit) and then used a self tapping screw to secure. The nut you see is nothing more than a spacer to accommodate the screw length. Note that this needn't be overly tight because the actual strain of work it taken up by the little notched part that fits ever so nicely into the "dimple" on the sheave of the factory bell crank. The screw is really just holding it flush to the part. I even toyed with JB welding it on but wanted to be able to remove if necessary.

The servo cable is mounted using the kit pieces plus a short piece of bar stock (leftover axle from a defunct gas grill with wheels). The lower part of the bar stock is clamped to the throttle cable with the screw-band clamp, and the upper end serves as the anchor for the servo cable end, with the kit supplied clamp. This give me total control over the angle of the pull and the distance from the bell crank (number of beads). And I only drilled 1 hole in the bike!


Servo Unit:

Again relying on other published reports of installs, I wasn't entirely happy with the locations I was seeing in use. Some were too exposed to weather, others too exposed to engine heat. I ended up mounting mine inside the cockpit fairing, against the cowl stay. Although this did make accessibility to switch settings requires  cowling removal, I chose it because -

  1. I expected that if I ever needed to change settings, it would only be once or twice over the life of the install.
  2. This location was well away from engine heat sources.
  3. Is reasonably well protected from weather (rain).
  4. The servo throttle cable reaches the  throttle interface with no sharp bends. (routes across the back of the instrument panel, then a wide loop bend back along the factory wiring harness and under the faux tank cover)

I used NO hardware to secure the servo. It is secured entirely with two tywraps, cris-crossed over the pointed nose of the servo with the upper flat half of the unit snugged up against the frame stay. You can see one of the ty-wraps in the picture.

Vacuum Canister:

I originally went with other advice and tried to operate with out a vacuum canister, but I found that I could not hold steady speed up any sort of incline so I added a home made one a few weeks later.

I used standard PVC pipe, with two end caps. I drilled and tapped two holes for the two hose barbs, though had I heard it before then or figured it out on my own, I'd have only used one with a "T". You can see the barbs, hoses and even the check valve in this picture. One tywrap secures the canister to the wiring harness across the back of the instrument panel.

I tapped into the #1 carb for my vacuum supply.

User Control panel:

Last item of concern was the cruise control switch panel. Since it is made for use INSIDE a car (thus not exposed to weather) I took some extra care to ensure it would be safe from rain intrusion, yet still easy and convenient to use. First, I made up a metal mounting plate and cut a hole in it to handle the wires coming out the back of the switch assy. Then I mounted the switch to the plate using the supplied double-sided tape. Then, I mounted that whole assy to my already existing J&M CB/Intercom mount on the left handlebar. It is very easy thumb operation to control the unit. Lastly, I used a thick (durable- maybe 3-4 mils) piece of plastic  and wrapped the switch assembly, securing that with a tywrap.

Also, if you look close at this picture you can see the plastic armor wrapped wire harness which is the cruise control wiring and just to the left a bit you can see the servo throttle cable wending it's way back under the left fairing pocket.


 Other notes:

I set up using the tach wire to sense engine RPM. No magnets on the wheels.

I went with other's recommendations regarding setting the DIP switches, but later found I needed to make one adjustment. I changed the configuration from "high-power engine, light vehicle" to "normal". I felt with the high power setting the control was slow to engage and slow to adjust speed. I like the feeling that comes from the gentle "kick" when I engage the control and I only get that when using the "normal" setting. Now it engages such I know it is on and holds speed to +/- 1 MPH, even up hills.

I have put 20K on the bike since install and I use the cruise a lot. I LOVE it!