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Rostra Cruise Control installation on a Kawasaki Concours 14

Brian D. Felice


The usual disclaimers: Installing and using this kit is the responsibility of the person doing the work and operating the motorcycle. The information contained below is a guideline and represents what has worked for me. Your installation may be different and may require different materials and procedures. The installation of anything that controls the throttle of a moving vehicle has substantial risk both to the operator and others in the area. Be careful during the installation and use common sense.

The Rostra cruise control is a fully electro- mechanical device that requires no vacuum input. I installed one of these on my C-14 with good results. The installation of this unit is not entirely straightforward and the CC itself is not a device fitted to this specific motorcycle. Some fabrication is required as well as some 'on the fly' mounting and modification. Some parts of the installation are critical and not very forgiving. For example, drilling  the throttle arm requires a bit of skill and the arm itself is not easily replaced so there is only one shot at this.

I have to say thanks to Jim Saeger who spent a lot of time and effort researching and learning how the Rostra unit works and was kind enough to publish his work at: http://www.sdb-e.com/RostraGL1100i.pdf Jim's installation is on an older Gold wing but the information he provides is pertinent to any use of the Rostra unit and gives great insight as to how the unit works and reacts. I communicated with Jim several times during my installation and his help was invaluable, especially for an understanding of how the PID loop in the Rostra unit is structured. For anyone interested in greater detail of this unit I would suggest reviewing his work at:http://www.sdb-e.com/RostraGL1100i.pdf 

The Rostra instructions will be referenced throughout this document and can be found at the Rostra website (http://Rostra.com) under "Global Cruise Instruction Manual". You will need these instructions, along with the instructions for the switch you are going to use with the cruise control. You will also need the Kawasaki service manual to disassemble and reassemble parts of the motorcycle as needed to fit the cruise control. There are two basic steps to installing this CC unit: one is the mechanical installation consisting of the CC actuator, the throttle arm attachment, and mounting the control switch. The second part is the electrical wiring of the unit to the motorcycle. Please read this entire document before beginning installation.

Updated 27.January.08   Several changes have been made including the elimination of one relay and the removal of the special Kawasaki wiring harness originally listed. These parts are not needed and only served to confuse the installation procedure. The revised procedure also contains a different and better cable mounting for the Rostra CC unit to the throttle arm. It is no longer necessary to tap into the main wiring harness of the motorcycle; all wiring will be done under the seat, under the left top fairing cover and on the left side of the engine. This installation uses the clutch switch as the second method of shutting the cruise control down instead of the ignition monitor and engine over speed and works much better.

Updated 29.March.09 Three changes: the first is to use the much more common and less expensive switch 250-3592 without an engaged light. The second is to note that the Rostra CC unit will NOT enter diagnostic mode if the clutch wire (the NSS wire on the Rostra) is in use. This means that the clutch safety cannot be wired until after the Rostra is otherwise fully installed and has been tested using the on-board diagnostics. Finally, instructions are included to add an 'Engaged' indicator light to any installation of a Rostra CC on a C-14. This is useful if using the 250-3593 switch without the engaged light.

Installation should take somewhere between one and two days depending on installer skill, tools available and familiarity with the motorcycle.

The CC unit is made by Rostra Precision Controls Inc. It is a well made, robust and waterproof unit and the company is excellent to deal with especially regarding unusual applications such as motorcycles. http://www.rostra.com/cruise-control.htm  The actuator itself is approx. $150, and the switch with engagement light is approx. $40. The switch without the engagement light is approx. $19.

The requirements are:

The CC unit itself: Rostra Universal Cruise Control Kit, part no. 250-1223

A control switch: I used the standard switch with illumination, part number 250-3592. Note that you can also use the standard switch that is also supplied with the Audiovox unit, part no. 250-3593. These switches are almost identical except that the second one does not have an light to indicate the unit is engaged.

A relay for the brake light signal. I used a relay that I purchased locally but would recommend the one that Murph's sells because it comes with a wiring harness. It is part no. MU-141 at http://murphskits.com  around $10.

Optional: an additional relay identical to the one listed above if the switch used has the 'engaged' light (switch # 250-3592). If you are using the standard switch without an 'engaged' light like the one usually supplied with the Audiovox unit (Rostra #250-3593) you will not need this relay.

Also needed are various wiring connectors, such as Posi Taps, bullet connectors (4 mm, or .156 diameter) both male and female, electrical tape, possibly some extra wire (small gauge, black, multi strand), soldering iron and solder, tie wraps, common hand tools, and an electric drill with a 5/32 inch drill bit, some sweat and a small box of dirty words. Most of these things can be picked up locally and also substituted for something similar; for example, instead of Posi Taps you could solder the wires together and cover them neatly with electrical tape. Note that this document is more of a guide than an absolute instruction sheet.

One 2008 or 2009 Kawasaki Concours 14 or GTR14, any color.

The left center fairing, the left forward fairing and the left fairing cover need to be removed to do this installation, along with the saddle.

There are two major components to the Rostra CC, the actuator itself which contains the electronics as well as the mechanical components in one package and will be mounted under the motorcycle's 'clothes', and the switch which is mounted on the handlebars. I installed my actuator on the left side, front frame brace. This is a warm location but the unit has been there for quite some time now and has survived the heat as well as weather exposure with no ill effects. No modification of the Rostra mounting bracket or the motorcycle is necessary to mount the servo unit in this location.

Fig. 1

Entire actuator installation

Fig. 1 shows the left side of the motorcycle with the center and forward mid fairings removed and the CC installed. The CC actuator is on the left of the frame just behind the radiator and the cable exits up and wraps around the entire inside of the fairings to end at the bracket just to the right of the main wiring harness (gray). The cable mounting bracket mounts to the back of the left side frame brace using the stock bolt. The wiring harness from the Rostra unit is just to the right of the CC actuator and is wound in electrical tape so that the brightly colored wires do not show through the cooling vents once the fairing is mounted. The actuator is mounted to the standard bracket that comes with the kit and attaches to the frame using the stock bolt already there. Nothing needs to be cut or altered. Position the Rostra servo unit so that it is not touching either the coolant overflow tank hoses on the right or the radiator hose or elbow on the left. The control cable exits the Rostra unit pointing up and curves around inside the fairing to the left, back down and then to the right until the end points up toward the throttle arm. The Rostra control cable must NOT be pinched or buckled anywhere and must end up free to move using nothing but your fingers.




Fig. 2

Dip Switch Settings

The actuator uses 12 DIP switches to configure it. They are grouped by function; see installation manual for details on the various functions and choices. For the C-14 I used the following settings:

1 2 3 4 5 6 7 8 9 10 11 12


The Rostra can use the pulse train from the vehicle speed sensor directly once it is set for its highest count rate and to receive a square wave (DIP #'s 3 through 6 and 10); these settings are correct for use in a C-14. The rest of the DIP switch settings are dependant on other components used and possibly user preference. Switch # 1,2 and 7,8 and 9 control the way the unit responds to changes in vehicle speed as well as overall system behavior (the PID loop). If the cruise control does not hold speed accurately enough set according to the above chart, you can switch #7 to 'ON'.  See Jim Saegar's page for an excellent and in-depth explanation of these settings; http://www.sdb-e.com/RostraGL1100i.pdf

The diagnostic LED is just to the right of the DIP switches in Fig. 2. You will need to see this LED when testing the unit after installation.



Fig. 3

Throttle arm drilled

Fig. 3 shows the throttle arm drilled for the Rostra cable attachment. The position and size of the hole are important. Diameter is between 9/64" and 5/32", the hole shown is 9/64" but 5/32" is almost the same size and it is easier to find that size drill bit. The farther the hole is located to the right the better the cruise control will work. Be careful when drilling the hole in the throttle arm; do NOT drill through anything behind the throttle arm by accident such as the number one injector, and do not allow the throttle arm to move while drilling it as that will most likely break the drill off in the arm. The left side frame brace has to be disconnected and rotated out of the way but does not have to be removed.



Fig. 4

Throttle arm and attachment cable

NOTE: the 6-32 screw must be short enough that it does not stick out past the nut. It was trimmed after installation and not left as long as shown in Fig. 4

Fig. 4 shows the cable attachment to the throttle arm. A 6-32 pan head screw is installed through the drilled hole from the back. A cable end, included with the kit (part number G6), is captured between two washers and clamped onto the throttle arm using a nut. The screw must not stick out more than about 1/16" past the nut or it will contact the frame brace as the throttle moves. This is a critical part of the installation for several reasons: 1) there is very little room around the throttle arm as the arm rotates and both the head of the screw as well as the end of the stud sticking through the arm may strike something. 2) the CC actuator cable has to be reasonably straight and in-line with the cable sheath and perpendicular to the throttle arm. 3) the cable MUST NOT hang up on anything as the throttle is opened and closed. Also make sure the cable going to the Rostra CC moves out of the way to a safe place as the throttle is opened while the cruise cable is left stationary. If the Rostra cable drags or hooks on anything adjust the geometry until it is free and clear for the full throttle travel. I mounted the end of the Rostra cable using a bracket similar to the 'E' bracket supplied in the kit. It can be seen in Fig. 1, mounted on the right side of the left frame brace. The mounting bracket must be positioned reasonably straight under the throttle arm, and not allow the throttle cable to touch anything as the throttle is moved with the Rostra CC unit or the throttle grip alone. Check this carefully and make sure the throttle moves freely!


Fig. 5

Rostra connection to throttle arm.

Follow the directions from Rostra to thread the throttle cable, then thread on the snap in adapter, G17 as shown in Fig. 5 Adjust the length of the throttle cable threaded through the adapter to adjust the cable free- play. Leave some play in the Rostra cable so it does not hold the throttle open.



Fig. 6

Control switch and mount

I mounted my control switch on the right hand handlebar because my GPS is mounted to the left handlebar and there is not enough room left for the CC switch. The bracket is a piece of stainless steel sheet I already had on hand. It is cut to shape, size and drilled to fit on the upper brake master cylinder mount and uses the factory bolts already there. There is also a mounting bracket available from Murph's (http://www.murphskits.com/product_info.php?cPath=130_133&products_id=349).  The switch is not waterproof so I covered the back and all seams with black RTV sealant. I also mounted the switch to the stainless plate with RTV sealant and used tie- wraps to hold it in position overnight. The wiring harness is wrapped in electrical tape for appearance only and follows the handlebar stanchion down to the upper triple clamp and then goes across to the left side of the fairing where all electrical connections are made. Note that this switch has the 'engaged' light on it. Any other Rostra switch can be used in place of this one but I wanted the engaged indicator light on mine.


So the actuator is mounted, configured and connected to the throttle arm, and the control switch is mounted. Next is the wiring of both units to each other and the bike. I will start off with what I did but also add other suggestions and methods. My installation was a learning experience and I would do some things differently the second time. I have also now seen other people's installations and honestly prefer some of their methods to the mine. What I did works fine but I think there are easier and better ways to accomplish the installation.


1) The actuator itself and the switch both have a 4- pin connector; wire them according to color and plug them in on the left side of the bike near the left air intake.

2) Gray Rostra to Pink VSS wire. Note: you must tap into the pink wire in the VSS harness, not the main harness. The color changes after the VSS connector and pink is no longer valid. Be careful with this wire as it is connected directly to the motorcycle's ECU. This is the only ECU connection the Rostra requires.

 Vehicle Speed Sensor (VSS):  Rostra Gray wire: The VSS is a signal generated by the bike as a function of well,... vehicle speed. It is a series of square wave pulses at 5 Volts that the Rostra CC will use to determine vehicle speed and vehicle speed change. The good news here is that the pulse train rate in Pulses Per Mile (PPM) and pulse type are directly compatible with the Rostra CC so that no manipulation of this signal is required. The Gray wire coming from The Rostra unit is connected directly to the pink wire in the VSS cable. I found it easiest to remove the VSS from the bike to make this connection; just remove this single bolt that holds the VSS in place and the harness connection. I soldered a wire to the Pink wire in the VSS harness but a Posi Tap can also be used. I also used a female bullet connector on the VSS harness to allow it to be plugged into the Rostra and also to allow the VSS or Rostra units to be removed at a later time. See Pic. below.

Fig. 7

Vehicle Speed Sensor and wiring

The harness under my thumb is the VSS harness that comes with the bike. The harness above my fingers that the bullet connectors and wire feed into is the harness for the Rostra and just wrapped with electrical tape. You can also see the bottom of the Rostra throttle cable mount and throttle cable in this picture. The VSS itself is the rectangular unit visible on the top of the left side engine cover. It is retained with a single screw and is O-ringed so there is not gasket to replace.

3) Light green Rostra wire to Black / white dot on the motorcycle. Note: Do not attach this wire until after the diagnostic procedure is done. The Rostra will not enter diagnostic mode if the clutch wire is connected to the motorcycle. Make the clutch wire to the Rostra NSS the last connection after all diagnostics are completed but before test riding with the cruise control.

Fig. 8

Wiring under the top left fairing cover (black cover)


The clutch switch will be used as the second method of shutting the Rostra CC unit off. Anytime the clutch is pulled in while the CC is engaged, it will disengage automatically and the engine will return to idle. Locate the black boot under the upper left fairing cover. Inside the boot is a wiring harness with a black connector. On the back of the connector (the side facing the back of the bike) there is a black wire with white dots, this is the clutch switch wire. Attach the light green NSS (neutral safety switch) wire from the Rostra unit to this wire. In my installation the Rostra wire was not long enough so I added some other wire (it happened to be green and gray but whatever color you have around will do) and a pair of bullet connectors so the wiring can be separated from the bike later if necessary. Do not cut the clutch wire, just carefully remove some insulation and solder a wire to it and then tape the joint as shown. You can also use a Posi Tap here instead of soldering.


Pin on Relay 87 87A 85 86 30
Wire connection Blue brake
light on motorcycle
Ground Ground Blue  brake
light on motorcycle
Violet wire
on Rostra

Fig. 9

Tail light and rear accessory lead under boot

5)  Fig. 9 shows the wiring at the rear of the bike under the seat and behind the ECU. Remove the seat, remove the tools and remove the toolbox ((4) screws in the corners). After the toolbox is removed, slide the ECU at the very back of the bike forward until it is free and out of the way. DO NOT disconnect it. Under the ECU there is a black rubber boot. Inside the boot are several connectors and a pair of accessory leads. Connect contacts #86 and #87 on the relay to the BLUE wire that goes to the tail light connector inside the black boot. Connect contacts #85 and 87A to the male bullet connector under inside the black boot (this is the ground connection of the accessory leads) using a female bullet connector. Before closing this area up, turn on the motorcycle's ignition and verify that the relay 'clicks' as the brake light is turned on.


6) Power and Ground for the Rostra actuator and Rostra switch: The instructions that come with the Rostra use two different inputs for the power connections; one that is switched with the ignition and one that is 'on' or 'hot' all the time. Also Rostra uses an additional _12 volt wire to connect to the hot side of the brake circuit for safety. I did not wire mine this way as I wanted to make sure the Rostra was not powered up when the ignition was off and simply connected all hot or +12 volt connections to the auxiliary wires under the top left black fairing cover. This method may be less safe than what Rostra instructs to do as a brake light circuit failure on the bike would not be detected the way I wired it. I also picked up ground at the same place as there are a pair of bullet connectors in the black boot that are available. I also made all the switch +12 volt and ground connections at the same time. What I did is as follows: From the Rostra actuator, take the following wires:

Brown from Actuator (with 10 amp in-line fuse)

Red from Actuator (with 4 amp in-line fuse)

White from switch

Gray from switch

Additional wire #1 for engaged light, any color (see below)

Additional wire #2 for engaged light, any color (see below)

Connect them all together, leaving the fuses in-line, and then connect them to the +12 volt wire on the bike using a male bullet connector on the Rostra side. These bullet connectors are locate under the black upper left fairing cover, in the same rubber boot that the clutch switch wiring is located. See Fig. 8 for a picture of this rubber boot. The female bullet connector under the rubber boot is +12 volts and the male bullet connector is Ground.

Next take the following wires:

Blue from switch

Black from switch   

Black from Actuator


Connect them together and then connect them to the ground wire on the bike using a female bullet connector to the accessory lead located in the rubber boot from Fig. 8

Using switch #250-3593, there is also an engaged light on that has to be connected to the actuator. A relay or transistor must be used to 'flip' the operation of the actuator's output. My suggestion is to purchase an additional relay identical to the one used on the brake light signal and wire it as follows:

Orange wire from actuator to coil of relay (#85 on relay)

Additional wire #1 to common conn. on relay (#30 on relay)

Additional wire #2 to coil of relay (#86 on relay) 

Pink wire from switch to relay (#87 on relay) 

The relay can be tucked into the area where the rubber boot is in Fig. 8 and secured using a tie- wrap to the harness there.


Test procedure: Test the entire installation before installing the fairings in case there are any problems. Make sure all testing procedures work correctly before riding the motorcycle!

29.March.09 The Rostra will not enter diagnostic mode if the NSS wire is connected. If you have already connected this wire, temporarily remove to test the Rostra installation. Connect this NSS wire after all diagnostics are completed and before actually riding the motorcycle.

1) Test the Rostra switch: Turn the ignition on. The background lights in the cruise control switch should be illuminated green. The 'On / Off' switch should turn the orange power light on and off. If this does not work, check the fuses in the Rostra cables, the accessory fuse on the motorcycle and the Rostra switch wiring. Correct any faults before continuing.

2) Test the brake relay: Turn on the ignition and using either the front or back brake, flash the brake light on and off. The brake light relay will 'click' indicating it is operating. If it does not work when the brake light is on, stop fix this before proceeding onto the next step.

3) Test the brake relay to Rostra connection: Refer to page 20 of the Rostra installation manual. There is an error in the instructions on how to enter the diagnostic mode: you must hold the 'Resume /  Accel' switch on the control switch 'on' while turning on the ignition for both a NC and a NO switch. Follow the instructions and remove the cover over the DIP switches on the Rostra unit. When the brake light on the motorcycle is activated, the LED on the Rostra should also illuminate. If this does not work correctly correct this before moving on to the next step.

4) Check the VSS sensor at the Rostra: Put the bike up on the center stand. Press and hold the 'Resume / Accel' button on the Rostra switch while turning the igntion on to enter the diagnostic mode. Do not start the motorcycle. While the ignition is on, the motorcycle is in neutral and the Rostra is in the diagnostic mode, reach down and rotate the rear wheel. The diagnostic LED should flash on and off as the wheel rotates. Check this carefully to make sure the LED flashes faster as the wheel is turned faster. This will verify that the Rostra is picking up the signal from the VSS. If it does not work, check the VSS wiring and make sure the DIP switches are set correctly on the Rostra unit.

The last thing to check is the throttle movement one more time. Check to see that the throttle moves from idle to WOT (wide open throttle) without ANY binding or interferance. Use a good light and carefully watch the throttle arm as it moves through its entire arc to make sure everything clears and that the Rostra cable cannot hang up on anything on the motorcycle. Also check that the Rostra cable is not touching anything as it moves as it will eventually cut through whatever it is touching.

If all the lights work on the Rostra switch and the Rostra diagnostic LED indicates the system works correctly, and the throttle operates correctly, it is time for the acid test. When engaging the Rostra, there are three ways to turn it off: One is by using either brake to activate the brake light, another is by pulling the clutch in to activate the clutch switch (NSS signal on the Rostra), and finally by pressing the 'Off' button on the Rostra control switch. Take the bike out for a ride at about 40 MPH or so in 5th or 6th gear on a level road. Hold the bike at a steady speed and turn on the Rostra unit and press the 'Set' button. Slowly let the bike's speed drop a little bit (about 3-5 MPH or so) and the Rostra should engage and open the throttle slightly. You should be ready to disengage the unit by tapping a brake and pulling in the clutch at the same time just in case something does not work correctly. Once engaged, the Rostra unit will hold the bike at a reasonably steady speed regardless of wind or hills.

A couple of notes:

The switch I used is somewhat more expensive than the switch without the engaged indicator. Otherwise they perform the same. This is a personal preference and not necessary to use the Rostra unit. The switch without the engagement light is available from Murph's.

The system works quite well overall. The CC will engage at a minimum of 20 MPH and will work to at least 120 MPH. The PID loop (the control behavior) is controlled by several of the DIP switches as well as the geometry of the throttle arm connection. There may well be a better set of settings than what I am using and if you experiment with this please let me know what you find. Again, Jim Saeger has done a lot of work in this area and his page is an excellent reference for Rostra tuning.

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