Kill Switch on AC vs. DC CDI By jstluise (Read 16,646 times)

[jstluise]

Getting ready for some rewiring on the 11 pole upgrade and DC-to-AC CDI conversion. Quick question about the kill switch.

With the existing setup (DC CDI), the kill switch functions by grounding the PICKUP COIL TERMINAL (TRIGGER WIRE) on the CDI.

The AC CDI has a terminal devoted to the kill switch (ground terminal to kill). But, I was wondering: Will grounding the TRIGGER WIRE with the AC CDI still result in killing the ignition?

If it does, then it will save me some rewiring because the circuitry to ground the TRIGGER WIRE already exists, and I can just leave the kill switch terminal on the AC CDI disconnected.

I could swear I ran across something on the forums that said it would, but I can't seem to find it again...

[tvnacman]

Well if you have ground at the kill switch and the the AC CDI has a pin just for a kill circuit . I would just pull a wire from the switch to the cdi . I'm not sure on your scooter are you sure it grounds out the trigger ? Could it be interupting the dcv feed from the ignition switch , so could it be power at the kill switch and not ground ?

Jojn

[jstluise]

Aug 10, 2012 0:36:06 GMT -6 tvnacman said:

Well if you have ground at the kill switch and the the AC CDI has a pin just for a kill circuit . I would just pull a wire from the switch to the cdi . I'm not sure on your scooter are you sure it grounds out the trigger ? Could it be interupting the dcv feed from the ignition switch , so could it be power at the kill switch and not ground ?

Jojn

Well its no problem me wiring up the kill switch to the AC-CDI. It would just be one less thing I would have to do if the current circuit works.

The ignition switch does ground out the trigger, but it also disconnects the DC power to the CDI, now that I look at it more closely. So, its not necessarily the grounding of the trigger that is killing the engine.

The wiring diagram doesn't show the KILL SWITCH, which would ultimately tell me everything...I guess I'll have to go check it out on the scoot.

Well it looks like I posted this prematurely...I'll have to go check out the wiring on the scoot. FWIW, here is the part of the wiring diagram:


When the ignition is ON, BAT1 & BAT2 are connected. When the ignition is OFF, IG & E are connected (thus, grounding the L/Y trigger wire).

[JR]

The setup will work just fine with the AC CDI. Even on the DC setups the igntion switch is the same. The key switch is a two way switch as in N/O and N/C. The AC type CDI works just like the DC one so simply use the L/Y wire to the kill wire location on the new AC type CDI.

Also this means that your side stand switch will work just as it always did and your emergency kill switch on the handle also. This will be a simply install.

JR

[jstluise]

Aug 10, 2012 8:46:17 GMT -6 JR said:

The setup will work just fine with the AC CDI. Even on the DC setups the igntion switch is the same. The key switch is a two way switch as in N/O and N/C. The AC type CDI works just like the DC one so simply use the L/Y wire to the kill wire location on the new AC type CDI.

Also this means that your side stand switch will work just as it always did and your emergency kill switch on the handle also. This will be a simply install.

JR

That's good to hear! That will simplify the install of the new AC CDI a bit. All I will have to do is hook up the AC power wire from the stator, and disconnect the B/L wire from the CDI plug (which was originally used for DC power on the DC CDI).

Thanks!

[jstluise]

Well I got out and did some testing on the electrical system. Here is what I found.

The kill switch on my scoot (the one on the handlebar) is in line with the B/L wire off the DC CDI. So, it interrupts the DC power supply to the DCI to kill the engine; it DOES NOT ground the trigger wire like I suspected.

Therefore, in order to keep my kill switch working, all I have to do is disconnect the power side of the kill switch and connect it to ground. No problem. This will ground the kill wire of the CDI and kill the motor when the kill switch is used.

To kill the engine using the key, the B/L wire from the CDI should also be connected to the IG terminal on the ignition switch (see schematic that I posted before). This will ground the wire when the key is turned off.

There, now the engine can be killed by either the kill switch, or the key.

But, the problem I see is that the trigger wire is already wired to the IG terminal, and I am not sure if wiring the B/L wire from the CDI to this same terminal will cause issues or not. Essentially, this shorts the kill switch wire and the trigger coil wire. I see a couple options:

1) Disconnect the trigger wire from IG on the ignition switch. This will no longer ground the trigger wire when the key is turned off. I am not sure what the purpose of grounding this wire is in the first place, so maybe this would not be a good idea.

2) Test to see if grounding the trigger wire will kill the engine. If this is the case, the wiring to the ignition switch can remain the same because turning the key off will ground the trigger wire and kill the motor.

Unless someone can come up with answers about the purpose (and effect...ie does it kill the motor?) of grounding the trigger wire, I guess some testing will be required. If the grounding the trigger wire doesn't do anything, the motor will remain running after the key is off, since the AC CDI isn't dependent on the DC power from the R/R.

[JR]

You are correct on all of your assumptions but the AC CDI has an independant kill wire;



So red/black from new 11 coil stator to AC power on CDI
blue/white or yellow/blue to pulse on CDI
Green to ground
yellow/black to coil
key switch and handle bar wire to AC kill terminal

Now on your key switch without looking at the diagram it's normal to have a 12Vdc wire from the battery. This feeds the acessories to the scooter, horn, brake lights, turn signals etc. So leave that be.

Now on the handle bar you are right, ground the feed to it and use the B/L wire to go to the kill terminal to the CDI, that easy and now done.

So the key switch like all other key switches is a two way switch N/O and N/C. So use the same battery feed wire to the switch. Use the same wire that feeds the accessories minus the old DC wire to the CDI. On the side of the switch that is N/C with the key off put a ground wire to one terminal and then tie the other terminal into the B/L you now have going to the AC kill terminal on the CDI.

Now if this won't work then there is another option so let me know, either way we can fix it so when you turn the key off it'll die and also with the handle bar kill switch too.

Remember on a AC type CDI you simply ground it out while on a DC type you cut the voltage supply. On the AC type CDI voltage to it does not stop until the engine stops, the engine makes it's own current. The DC type CDI loses voltage from the battery when you tun the key off.

But when you kill the engine by either means to the CDI you have no power from it to the coil thus no spark.

JR

[tvnacman]

Leave the trigger wire alone , give it direct connection to the Cdi . Pick up a ground on one side of the kill switch , then send to the Cdi kill port . Wire the ac feed off the stator direct to the Cdi . You can feed power and pulse to the Cdi all the time , if the kill port is grounded it will not run . Be sure to connect on the out side of the kill switch/Cdi side so when the ignition switch is off your sending ground to the Cdi kill port .

John

[jstluise]

I guess I should have been more succinct with my last post. I understand completely how the kill wire is wired and works, but the issue was the existing connection of the trigger wire circuit to the ignition switch.

If you look at the wiring diagram you will see that the L/Y wire (highlighted in cyan) from the trigger coil is wired to the CDI AND the N.C. terminal of the ignition switch. This grounds the trigger circuit when the key is off.

The N.C. terminal on the ignition switch is what I want to use for my kill switch, but it is already occupied and I don't know if connecting to it (without disconnecting the trigger wire from the ignition switch) will cause any problems.

I hope that makes more sense now.

[JR]

Yes let me look the diagrm over again and we'll put our heads together and make it work.

[jstluise]

Aug 12, 2012 17:30:35 GMT -6 JR said:

Yes let me look the diagrm over again and we'll put our heads together and make it work.

Cool, thanks! From the sounds of it, there really isn't a reason for the trigger wire to be switched to ground when the ignition is off (is there?). If that is the case, then I'll simply disconnect it and wire up the kill switch as planned.

[JR]

Yes it makes perfect sense as to what you said but how they wired this doesn't make any sense. LOL I have two scooters with the DC system and just like the AC systems they ground out ony the CDI.

I apologize I should have looked at the diagram again and I did and it's simple.

We know that the AC system's method of killing the engine is by grounding out the CDI only and they do not ground out the trigger or the coil which from what I see in your diagram is what they have done here?

You've got to do a little rewiring but you know that.

On the key switch the red and black are a done deal leave them alone. On our new 11 coil AC type CDI system we will NOT ground out the trigger or pulse coil, absolutely not necessary.

So after installing the 11 coil stator run a single wire from the trigger or pulse coil to the proper pin on your new AC type CDI.

Run a single wire from the AC feed wire (usually red/black) to the proper pin location on the CDI.

Wire the 3 yellows to your new R/R

Of course hook up the new CDI to a ground wire on the proper pin.

Run a single wire from the new CDI from the proper pin to the coil and make sure the coil is grounded, if it is a two wire coil then one wire to the CDI and the other is a ground and also if it has a kill wire from the key switch disconnect it, if you can't use it then just terminate it.

Then from the key switch take the b/y wire and use it for the ac type CDI kill wire. Also as we said ealier on the handlebar kill switch ground one terminal and then tie the other wire into the b/y wire that is now the CDI kill wire.

Also we now do not need the 12Vdc wire from ther key switch to the CDI because it's now a stator fed AC system, terminate the wire.

The scooter will run and before you even start it or for sure put any plastics back on you can use your multimeter to test the kill wire functions by ohming it out.

The AC system is simple to kill the engine ground out only the CDI.

JR

[jstluise]

Great sounds good! Yeah, I have no idea why they have it wired up the way they do (grounding the trigger wire).

I'll disconnect and the rest will be easy. I went through all the wiring yesterday to make sure there weren't any surprises when it came to the re-wire; this was the only one.

Have a make a run to get some wire, and I am still waiting on some connectors from digikey. Then I'll be able to get this project done with!

Thanks for the help!

[tvnacman]

Aug 12, 2012 17:57:19 GMT -6 JR said:

Yes it makes perfect sense as to what you said but how they wired this doesn't make any sense. LOL I have two scooters with the DC system and just like the AC systems they ground out ony the CDI.

I apologize I should have looked at the diagram again and I did and it's simple.

We know that the AC system's method of killing the engine is by grounding out the CDI only and they do not ground out the trigger or the coil which from what I see in your diagram is what they have done here?

You've got to do a little rewiring but you know that.

On the key switch the red and black are a done deal leave them alone. On our new 11 coil AC type CDI system we will NOT ground out the trigger or pulse coil, absolutely not necessary.

So after installing the 11 coil stator run a single wire from the trigger or pulse coil to the proper pin on your new AC type CDI.

Run a single wire from the AC feed wire (usually red/black) to the proper pin location on the CDI.

Wire the 3 yellows to your new R/R

Of course hook up the new CDI to a ground wire on the proper pin.

Run a single wire from the new CDI from the proper pin to the coil and make sure the coil is grounded, if it is a two wire coil then one wire to the CDI and the other is a ground and also if it has a kill wire from the key switch disconnect it, if you can't use it then just terminate it.

Then from the key switch take the b/y wire and use it for the ac type CDI kill wire. Also as we said ealier on the handlebar kill switch ground one terminal and then tie the other wire into the b/y wire that is now the CDI kill wire.

Also we now do not need the 12Vdc wire from ther key switch to the CDI because it's now a stator fed AC system, terminate the wire.

The scooter will run and before you even start it or for sure put any plastics back on you can use your multimeter to test the kill wire functions by ohming it out.

The AC system is simple to kill the engine ground out only the CDI.

JR

very well stated

John