© 2014 Drake Smith - Please do not
use or reproduce this elsewhere. Feel free to link to it
Electronic Cruise Control on a K75/K100
Control Disclaimer: This documents what I did in
the hope that others might find it useful. Rostra (and other
automotive cruise control manufacturers) specifically state that
they do not condone the use of
their cruise control products on motorcycles. You are modifying
the throttle control on a vehicle that is dangerous enough in
the first place. Therefore, if you do this then you do so
at your own risk and I am not
liable for anything that happens as a result of your reading
For K1s, K100RS4Vs and K1100s the wiring will be the same but
you'll probably need to figure out a different way to hook it up
to the throttle linkage since the throttle bodies are different
than on a K75/K100. I think the way I did it for my
Audiovox CCS-100 installs would work well.
It's a good idea to disconnect the ground from your battery
before performing any electrical work on your bike.
The Cruise Control Unit
In the past I've installed
something like fifteen or so of the Audiovox CCS-100 vacuum
cruise control units on various K bikes with excellent
results. However, Audiovox stopped making them several
years ago and there's still high demand so they usually sell
for $175 or more on Fleabay these days. The site Murphs' Kits
sells exact replicas of them for $180. (plus shipping I
Since I've run out of "spare"
CCS-100 units, I decided to have a go at installing an
electronic cruise control. The one I'm installing goes
by two names. One name for it is Global Cruise Electronic
Cruise Control and the other is Rostra 250-1223 Universal
Cruise Control. They also sell for about $175 plus
shipping these days. However, several months ago I
found a new one, without a control switch, on a $99.99
Buy-It-Now with free shipping so I snapped it up, knowing
I'd probably need it someday. In the summer of 2013 I
found a turbo K75 to buy so that became the victim for my
pilot install of the 1223.
Here's the installation manual:
On my first few CCS-100 installs,
I used the control switch that came with it and mounted that
above the choke lever. Like so:
Even though I'd filled the
control switches with RTV to "waterproof" them, eventually
one of them leaked, shorted and failed. Then I came up
with the idea of using windscreen up/down switch from a
K1100LT to control the cruise control. This has
several advantages. First, it actually IS waterproof
since it was designed for a motorcycle. Next, it's an OEM
switch so it looks like it belongs there, unlike the
aftermarket look of the Audiovox or Rostra switch. Finally, it's
ergonomically more convenient to use.
The up button of the windscreen
switch functions as the Resume/Accel/"Tap-up" button and the
down button functions as the Set/Coast/"Tap-down" button.
"Tap-up" and "Tap-down" allow you to fine tune your cruising
speed once the cruise control is engaged.
As a "universal" cruise control,
the 250-1223, like the Audiovox CCS-100, has a set of binary
switches which allow you to configure the operation of the
1223 to your particular vehicle and type of installation.
These are located under the rectangular rubber cap on the
1223 control unit. You probably want to do this ahead of time on the
workbench. Up is on, down is off.
This table, from the installation
manual, shows how the unit should be "programmed" by setting
These are the switch
settings what seem to work best on a K75C. Different
models that are heavier or have more power may require some
experimentation to finetune the switch settings.
1 & 2 - Gain: These switches determine how
hard the 1223 pulls on the throttle when it kicks in. I have
them set at ON-OFF. (Low)
3-6 - Pulses/Mile: These are to set the
pulses/mile received from the speedometer sensor. A K
bike speedometer sensor puts out a little under 5,000
pulses/mile so I set these to ON-OFF-OFF-OFF.(4,000)
7-9 - Pull: Here are the 7-9 settings sorted:
8 Cyl Low
4 Cyl Low
6 Cyl Low
8 Cyl High
4 Cyl High
6 Cyl High
4 Cyl Extra High
6 Cyl Extra High
According to the Rostra website,
these switches determine how "fast" the
control unit pulls on the throttle cable. It's not
really clear from either Rostra's manual or website but I
believe that this is the correct sort order for these
settings. If it pulls
too quickly then you will have a jerky ride. If it doesn't pull
quickly enough then the cruise won't be able to accelerate
enough to maintain the set speed, when you're going up
a steep hill for example. Low in the table refers to low
weight to high horsepower ratio. Start with the lowest
setting, OFF-OFF-OFF, and work your way down the table to
I found that what worked best on
my K75 was ON-OFF-OFF. (4 cyl low)
10 - VSS Source: The speedometer sensor on a K bike is an
analog inductive device that generates a sine wav. Set this
11 - Transmission: Set this to OFF - for a manual transmission
12 - Control Switch: Set this to OFF. (For either the windscreen
switch or the switch that comes with it. Both are normally
supply: Since the 1223 uses electrical power to pull
on the throttle it uses a fair amount of power compared to a
vacuum cruise control so I added a switched fused relay to
power it. Using standard Bosch terminal designations,
here's how I wired the relay:
Tapped into the
wire of the white four terminal alarm connector found in the
relay box. (Switched power from #7 fuse.) This turns the
cruise control on when the bike is turned on.
Power in. I connected this to the
"always hot" terminal on the starter relay with a
ring terminal. I put a 15 amp fuse in this
brown wires of the
The wiring instructions in the
installation manual that came with the 1223 are horrible so I did
some poking around on The Internet to gain a better
understand of the wiring.
According to the installation instructions you're supposed
to hook this up to the "hot" brake switch wire (green/black
on a K bike rear brake switch) but that wire is just
switched power so I ran that to the relay output power above
to keep things simple.
This is the main 12V+ power to the 1223. That is hooked up
to the relay output above since I'm not using a power switch
and it will just be on whenever the bike is turned on.
This is the main ground for the 1223. I've read that the
1223 can be sensitive to poor grounding so I connected it to
the negative terminal of the bike's battery using a ring
When the brake light goes on, this wire senses 12V+ and
disengages the 1223. You can tap this into the (gray/yellow)
brake light wire. Since I have LED brake
lights, I added a normally closed
PCB relay that
grounds the violet wire when the brake light is not lit.
Wire: This wire
monitors the pulses from the speedometer sensor so the 1223
knows to speed up or slow down in order to keep you at your set
speed. Tap that into the yellow speedometer sensor
wire under the right side battery cover.
94+ K1100s have a slightly
different connector but the wire colors are the same -
Wire: (Optional if you
tap the blue wire into the coil.) This
is the Neutral Safety Switch wire. It keeps the 1223 from
over-revving if you pull in the clutch or the bike is in
neutral. The 1223 disengages when this wire is
Since K bikes use the clutch switch to put 12V+ to the start button when the clutch is
pulled in, I used a normally open
PCB relay to send a
ground signal to the 1223 when the clutch is pulled in or
the bike is in neutral. I tapped the positive trigger
wire for the relay into one of the black/green wires (power
to the start button) at the connector for the right
As a safety feature, this wire monitors the RPMs at the
ignition coils to avoid the 1223 from going into run-away
mode and over-revving the engine. However, since I'm using
the clutch switch this wire does not need to be wired to the
coils. Per the installation instructions that came with the
1223, I grounded this wire to the negative battery terminal
with the main ground wire (black wire above) to avoid it
introducing "trashy" signals into the system.
Wire: This is the wire
for the Set/Coast/"Tap-down" button. I wired that to the
blue (down) wire of the windscreen switch.
This is the wire for the Resume/Accel/"Tap-up" button. I
wired that to the gray (up) wire of the windscreen switch.
Green Wire -
This provides switched 12V+ power to the windscreen switch.
I tapped that into the green/brown wire of the alarm
connector in the relay box.
(Optional.) This wire puts out a ground signal for an
indicator lamp when the
cruise control is engaged. Since the bike is an 86+
non-ABS bike I wired that up to an amber led I installed in
the unused indicator next to the low fuel light in the
instrument cluster. I'd wanted to use a green LED for this
but wavelengths of a green LED and the red lens are too
different to let much light through. So I used an
amber LED instead which works much better as amber and red
wavelengths are closer together.
K75s & 2V
K100's: Another approach is to use the 1223's
orange wire to have your choke
indicator lamp in the instrument cluster double as a cruise
control indicator. All you need to do is tap the
orange wire from the 1223 into the
violet/white wire of the choke switch connector found
under the left side of the tank. Even if your K bike is a 91
or later that didn't come with a choke indicator there's
still a two wire connector (violet/white
and brown) under the left side
of the tank that goes to the choke lamp in the instrument
cluster. Connect the 1223's orange
wire to the violet/white wire.
Click on the wiring diagram below
to have a larger version open in a new tab for printing:
from installation manual:
K1100LT Windscreen Switch
The housing of the K1100LT left
combination switch is the same as a K75/K100 so it will
"bolt right up" to a K75/K100 choke perch. There's a
Phillips screw at the bottom middle of the face of
combination switch that holds the combination switch on. If
that hasn't been removed since your bike left the factory
then there can be some corrosion in the threads so be sure
to use a good screwdriver and lots of pressure to avoid
stripping the head of it.
For the headlight, horn and turn
signal, the K1, K100RS4V and K1100 models
use different combination switch wiring harness connectors
than K75s/K100s. Therefore, you'll need to graft the
connector from your old left combination switch to the
K1100LT combination switch with a windscreen switch.
However, both use the same wire colors so it's a
Control Body: I chose to install the 1223 in the
tail cowl of my K75. I drilled a hole in the lower left hand
corner of the tail cowl for the cable to pass through.
The Wiring: I encase all of the wires from the
control unit in an approximately 2 1/2 foot long section of
heat shrink tubing to bundle and protect them. (You don't
need to heat shrink it.) I run this out of the left turn
signal wiring hole in the lower left corner of the tail cowl
and then zip-tie the bundle to the left frame rail under the
tail cowl, similar to how the factory tail light wiring runs
along the right frame rail. Then, up near the battery,
I split off the various wires to where they need to go.
In order for the rear fender to
fit on the right rear corner of the frame, I cut a U for the
wiring bundle here:
(a.k.a. Servo Cable):
I modified the bracket that came with the 1223 as shown
Once I'd painted it black (while
listening to The Rolling Stones) I snapped the black plastic cable
holder into the square hole and mounted the modified bracket
to the left frame rail with a stainless steel hose clamp
above the throttle bodies:
And then attached it to the
factory throttle body adjustment screw between the #2 and #3
throttle bodies. DO NOT mess with that screw itself as it
should remain where the factory set it. I just put a
connector and a nut on top of it, that's all.
I used a ball chain end coupling and
installed it as shown:
Click on this link for a 1 page
installation "cheat sheet:"
Although it is doubtful that
anything will go wrong on your test ride, the red kill
switch is your friend. It is important to note that on
K bikes the kill switch cuts power to the brake light so if
you're testing it with traffic behind you then the vehicle behind
you may not be aware that you are slowing when you apply the
brakes after hitting the kill switch.
There's a diagnostic LED under
the rubber cap to the left of the DIP switches:
Turn the bike on while holding the up switch of the
windscreen switch. The LED should be off and the 1223
should be in diagnostic mode.
Press the down switch of the windscreen switch. The LED
should illuminate when the switch is pressed.
Press the up switch of the windscreen switch. The LED should
illuminate when the switch is pressed. If neither of these
illuminate, use a voltmeter to check that you are getting
12V at the windscreen switch's
The LED should illuminate when either brake is used. Check
that you are getting power to the 1223 if none of the above
actions illuminate the LED.
To test the speedometer sensor connection, with the bike in
neutral and on the center stand, spin the rear wheel. The
LED should flash.
To test the Neutral Safety Switch function switch, pull in
the clutch. The 1223 should disengage.
cruise control kit comes with several ScotchLok connectors
for tapping into existing wires. I've found these to
be unreliable and sometimes they will cut the wire you're
tapping into. I prefer to use Posi-Taps for tapping into
© 2014 Drake Smith - Please do
not use or reproduce this elsewhere. Feel free to link
to it though.