Connecting the 'Tach' wire on a Rostra CC

T_C

T_C

Joined
Mar 8, 2012
Messages
4,322
Location
St. Louis, MO
Bike
2005 St1300
STOC #
8568
Looking through the threads I see where the blue wire on a Rostra cc unit (standard electric drive universal unit) is tapped onto the ignition coil. Specifically onto the high voltage side of the coal.
This is correct, right? The Tach feed is just picking up one pulse from the spark.

Is it just me or does this seem like a bad idea. A 22awg wire with standard (relatively thin) insulation going from your coil up along the frame and other thin wires to the main unit.

Anyone have problems with leakage from the wire?
 
No , do not hook it up to the high voltage side of the coil that goes to the plugs, let me look it up to what I hooked into , but it was the low voltage side definitely.
 
I soldered the blue wire from the cruise control to the Yellow/ blue stripe wire to the left side coil which was a skinny , thin wire. This wire just picks up the signal that the ECM puts out to "fire off" the coils at the proper moment. It looks like in the wiring diagram that the ECM is grounding that wire and the Blue/ yellow stripe wire on the right coil for the timing. (The Black /white stripe wires are feeding positive to the coils and several other control/components from the Bank Angle sensor relay.)
 
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I don't know if the ST1300 has much in common with the st1100 but on the 1100 wiring diagram :

http://illzoni.com/bikes/farkles/wiring_diagrams/right_40a.gif and http://illzoni.com/bikes/farkles/wiring_diagrams/right_40a.gif

You can see a yellow green wire connecting the tach to the ignition control module. On the bike you can see this wire attaching to the back of the tach with a screw through a spade. I put a spade on my Rostra blue wire and hooked it up to that same screw. Tested it by pulling in the clutch while CC was engaged and as the bike overrevved the cruise unit shut off; since that is its intended function, it seems to be an easy way to hook it in.
 
stowner said:
I don't know if the ST1300 has much in common with the st1100 but on the 1100 wiring diagram :

http://illzoni.com/bikes/farkles/wiring_diagrams/right_40a.gif and http://illzoni.com/bikes/farkles/wiring_diagrams/right_40a.gif

You can see a yellow green wire connecting the tach to the ignition control module. On the bike you can see this wire attaching to the back of the tach with a screw through a spade. I put a spade on my Rostra blue wire and hooked it up to that same screw. Tested it by pulling in the clutch while CC was engaged and as the bike overrevved the cruise unit shut off; since that is its intended function, it seems to be an easy way to hook it in.
Click to expand...

That worked great for me, too.
 
Yeah.. I just had a momentary brain fart. I was thinking it was picking up the HV side for some reason.

Mine is installed and working wonderfully. I made a small 'y' cable jumper with a male/female spade lug and inserted that into the feed side of the coil.
 
Jim Van said:
That worked great for me, too.
Click to expand...
Have you had your CC spontaneously shut off ? I have and I see that Seth has too. Was wondering if this tach attachment might be to blame. When it shuts off you have to recycle the on/off to re engage it, just like after an over-rev shut off. I am going to disconnect the blue wire tonight and see if the shut downs continue. I'll report back.
 
stowner said:
Have you had your CC spontaneously shut off ? I have and I see that Seth has too. Was wondering if this tach attachment might be to blame. When it shuts off you have to recycle the on/off to re engage it, just like after an over-rev shut off. I am going to disconnect the blue wire tonight and see if the shut downs continue. I'll report back.
Click to expand...

So far, after 100 test miles, no. Again, I'm connected directly to the Yellow/Green wire on the Tachometer.
 
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