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sandiegobrass 08-07-2007 11:03 AM

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[align=left]ROSTRA INSTALLATION IN A GL1100I[/align]
Click here to download the PDF install and testing document.

EDIT: the original pictures have disappeared, Jim has pdf that contains all of the information.

Rostra Installation Short Version with small pics 8-14-10 (1).pdf

download that file, and you can see the original article with the pictures.

[align=left]Above linked document edited: 8-10-07: No significant changes. Only cleaned up with minor edits.
[align=left]A number of people here have expressed interest in installation experience with the Rostra Electronic Universal Cruise Control (250-1223). R Kirby (tricky) has already reported one installation on a GL1200 although to date, he hasn‚€™t reported any operational experience. I have completed my installation on a GL1100i and have about3000 miles of use (testing) to date and can give relatively detailed summary. I‚€™ll just give an initial version here and if I complete any more tests, I‚€™ll just update this document.

Let me give the bottom line first, for those that don‚€™t want to wade to the end. It is working very well; I‚€™d give it about an A-. Above 50 mph, it works flawlessly and nearly as well as my GMC SUV (edit 10/15/07: and better than my recently acquired GL1500SE). And it works quite well 30 to 50 mph too, almost all of the time, but can get in situations (down hills, wind buffeting in traffic, tail winds) that cause it to uncomfortably correct to decrease speed when it would be a little better to be a little less harsh and let it coast. These, I think, are not unique to this Rostra installation but having to do with more general issues like Power/Weight ratios and a sensitive throttle linkage geometry for this motorcycle that really needs to be addressed to work optimally with a cruise.
[align=left]Although I did deviate somewhat from the typical motorcycle installation methods that I see on the Internet, I did demonstrate the same method (hooking directly to the short carb #4 linkage) somewhat successfully. I do believe that making the Rostra Electronic work with this short linkage setup is a bit of a crapshoot, and if you are not so lucky, you can find yourself spending a lot of time getting it sorted out. The problem is in how the VSS PPM settings affect gain (and Rostra customer service doesn‚€™t even understand). If you use the magnetic pickup system on a wheel with 6 magnets and set the ppm to 4000, you will coincidentally avoid most of these problems and have a useable cruise, however, if you try to use anything else (like another VSS signal or the tach, or the alternator, etc.) you may find yourself chasing your tail before you find a setting that works.[/align]
[align=left]Physical installation of the Rostra electronic is, I believe, a little bit easier than a vacuum unit since you don‚€™t have to deal with the vacuum lines and canister; the electrical connections are essentially the same. But in many cases you will spend all of the saved time (and then some) getting the unit properlytuned to have satisfactory performance, where, if you believe the glowing reports, the vacuum unit (Audiovox CCS100)appears to bepretty much a hook it up, set it and forget situation. That approach would not have been successful with this ROSTRA electronic installation (and maybe I am overly critical and would not have given a good grade to the Audiovox either). (Makes me want to buy one and do side by side testing, and maybe I will, but that will have to wait, too.).

A few things are left below as highlights, but all of the pictures are in the referenced document, not here.

Here are a few unique points:
LOCATION FOR MOUNTING: Between right bag and wheel attached to bag frame.

Gray wire
The gray wire is the Vehicle Speed Sensor (VSS) input ‚€¶ My choice is at the turn cancel unit connector (White wire with black trace). The VSS signal measures 9350 ppm.
Lt Green wire
The light green wire is the neutral switch wire and is attached to the GL1100i to accomplish both the clutch switch and neutral function.
Blue Wire

Not used but comments included on using the tach/coil signal as an input for the VSS (Gray wire).


Throttle Linkage: Uses 2" radius bar on throttle plate.
Gain, Timers And CPU Dip Switch Setting
Gain (1,2) (Start with LL: Off,Off)
Pulses per Mile(3,4,5,6) (Use 9650 for the ‚€˜83GL1100i: Off,On,Off,On or other as necessary for your application)
Engine Setup/Timer (7,8,9) (Start with 8cyl L: Off,Off,Off)
There is more to this setting than meets the eye‚€¶.
VSS Input (10) (Set to square wave signal; the 83G1100i VSS is square: On)
If you are using the magnets then sine.
Transmission (11) (Set to AUTOMATIC!!! : On)
This is not a transmission switch, just the question: Are you using the neutral wire
Control Switch (12) (Depends on the control switch you get; mine was open: Off)


As mentioned, the first ride was not satisfactory using the 1.5‚€Ě arm, the lowest gain, 9650 PPM setting, the 4 cyl L setup timer. It was much more aggressive than would be acceptable (at least for me). Again, let me digress and say what I mean by aggressive and sluggish: By aggressive, I mean frequent overcorrection by throttle changes that cause acceleration or deceleration not expected and/or are uncomfortable. (This is usually due to too much gain with either proportional and/or derivative terms that are too large.) By sluggish, I mean not correcting as soon as it should allowing slowdowns (and overspeeds) that are not abrupt but interfering and annoying (This is typically caused by not enough overall gain, or too much integral action and or not enough derivative.) In the following discussion, note that there are three things that Rostra provides as parameters (Gain, Setup/timer, and PPM setting), although they don‚€™t officially recognize PPM as a knob to twist. In addition, this installation has provided the length of the control arm as another parameter which is similar but not exactly identical to the Rostra ‚€œGain‚€Ě

Noting that shortening control arms, selecting higher gain settings, selecting higher timer/setup (meaning a more sluggish vehicle and farther down the list), and selecting higher PPM settings all increase ‚€œaggressiveness‚€Ě (and the opposite selections to make it more sluggish), the tuning experiments began. I add the summary of results here in shart form without discussion, but it should be evident from the chart below how things work. I have also attempted to theoretically calculate a ‚€œfigure of merit‚€Ě for each setting based on educatedestimates of the relative mathematical inputs that is normalized so thatideal is approximately 1.00. Higher numbers indicate a more ‚€œaggressive‚€Ě behavior and numbers lower indicate a more sluggish behavior. This should be looked at as more qualitative than quantitative. It is also incomplete as for verification by testing. Your PPM settings, in particular, may be different based on what you use for a VSS signal but what I want to emphasize is that this number is a parameter too, not just an input related to your VSS speed. The column called "Actual/Setting" is the ratio of your actual PPM divided by the selected PPM setting.

The color code is this:

Orange: Not Tested but not expected to yield a good result because too aggressive.
Light Blue: Not Tested but not expected to yield a good result because too sluggish.
Yellow: Not Tested but potentially could yield a good result.
Red: Tested and yielded an unusable result because too aggressive.
Dark Blue: Tested and yielded an unusable result because too sluggish.
Light Green: Tested and yielded a useable result but not the best.
Dark Green: Tested and yielded the best result so far.


exavid 08-08-2007 06:43 PM

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Good information here! Thanks.

sandiegobrass 08-08-2007 07:47 PM

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Thanks for the reply! (Wasn't sure anyone was actually reading it... )

I am still working on developing the data for using the Tach or the alternator for the Rostra VSS signal, so I will be back later....


tricky 08-08-2007 09:56 PM

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Excellent Info.

I havnt been able to get many miles in so far this year and was busy installing the external alternator etc etc so havnt been able to finish up with my Rostra, hopefully will get to it before the year is out :(

wexy 08-09-2007 01:22 AM

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Great info ,I have made this a stickey thread so it will stay at the top of the forum for a while .thank you of ryou great effort ,,Ciaran

AZgl1800 08-09-2007 08:43 PM

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876 Attachment(s)

I read thru your article all the way. Not because I need the cruise because I don't, the 1500 has one.

But because I have been there before with two different add on cruise controls in the past. I just wanted to see how your empirical data compared with what I noticed before.

Happy to say, they what you said compares very well with what I remember with the ones I installed more than 20 years ago.

Great article, thanks for sharing.

SB in SC 08-10-2007 06:25 PM

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Hom much is the final cost of the cruise control unit?

sandiegobrass 08-10-2007 07:16 PM

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I got about $220 in it.... 165 for the servo and brains and another 40 for the control switch.. then a few bucks misc and shipping... Jim

wilddoug 08-12-2007 04:40 PM

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I read your article and was very intrested. I have been pondering the idea of installing this type of c/c on my 81. Like you,I am not to crazy about the magnet on the wheel setup for the VSS. The only problem I forsee is that my 81 does not have a speed sensor for turn signals, in that mine does not have auto cancel signals. Although, the wiring diagram does show a speed sensor in the speedo head for use by the air suspension warning system. I was wondering if you had looked at this sensor for use as a signal source. I do have an oscilliscope I could test it with, but getting to a test point without removing the fairing does'nt look possible. If you have not tested, I will, although probably not too soon. Probably a winter thing. Too much good riding weather right now. Keep up the good work. The article was GREAT!!


sandiegobrass 08-12-2007 09:09 PM

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I'll look at the wiring diagram tomorrow, but I am not sure that will tell me much. I can say that the VSS signal for the turn signal canceling (for the '83) is, in fact, in the speedometer head (even though I tapped it at the cancel unit) and I would not be surprised to find out that the 82 and 83 speedometers are identical.. probably could check the speedometer part number too... Anyway, keep in touch.

Today was a bit of a failure for the coil signal conditioner... I put what I designed together, hooked it to the power supply and it got hot as a pistol... .. must have hooked something up wrong... as it should not do that..


edit... just checked.. different part numbers but the VSS part still may be the same..

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