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Discussion Starter · #1 ·
This forum is great! Just bought a 79 deluxe that hasn't ran for a few years as a project. The bike idles nice now, but both the ignition switch and the kill switch won't turn it off. I've checked the wires and they are good. I took the black/white wire from the CDI and tried touching that to the frame and still nothing. To turn it off I have to unplug the yellow and pink wires from the coils. Does this mean my CDI is bad?
 

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Welcome to the forum Ptown! Nice to see another local. While I have no help for ya, be sure you check out the regional section for the others in our area. Hope you get help soon, which I am sure you will from others that have more technical knowledge than I do.

Joel in the Couve
 

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The crappy answer for now is to stall it out.



But there was a post of two others who had killing problems. I'll go hunt it up.
 

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My guess is try a different CDI box. I think the wire broke somewhere between the CDI and the bullet connector. Or the CDI somehow shorted out the kill switch and it no longer can ground.





Like I said try a different CDI and see if that fixes your problem.



Maybe ramprat can help you test the CDI theory.
 

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Maybe ramprat can help you test the CDI theory.


My bike is TI, and I don't have any spare parts to work with. Floater Dave or Wootersen, Or jnovaman may be better resources. There are several others in this area. Sorry I can't help.
 

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My bike is TI, and I don't have any spare parts to work with. Floater Dave or Wootersen, Or jnovaman may be better resources. There are several others in this area. Sorry I can't help.




Guess I should have looked at the year of your bike first
oh well. Hope someone can help. I would but I am about 180 miles away.
 

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Discussion Starter · #9 ·
Ya mine is exactly like that other post. When I bought the bike I got a few boxes full of parts. I have another cdi, but it looks kinda beat up. I'll try that one and see if it does the same thing. I tested the ign switch and the kill switch with a volt meter. When either one is off, the wire that plugs into the b/w cdi wire is grounded so I'm pretty sure it's not the switches. I didn't want to try the other cdi because it is black and mine is gold, didn't know if they were the same on the inside. But I just read somewhere on here that they are the same so I'll try that out. Thanks guys for all the info!
 

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Yah they are the same just a slightly different year. Let us know how it goes and hope that the other CDI works.
 

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I taken a few CDI boxes apart and recall finding the track to the black/white wire

had burnt out on the first one.

I dont have the diagram here and dont play with CDI bikes much now my lads sold his

but from memory it works like this.



Power to the CDI enters via the blue wire and immediately runs through some diodes

and gets tapped off to the black/white connector before it feeds the charging caps

I guess you could by pass this by patching into the blue wire and connecting this

to the black/white going to the kill and ignition switches.

The end result would be the same as the kill switches just work by shorting stator output to ground to stop the motor.



To inject a note of caution, a current limiting resistor may help prevent any shock to the system as the motor winds down so I'd try say a 100 ohm in series with it first.

perhaps a 600+v diode as well?

You'll need to experiment here and its possible only a dead short will stop the bugger.



IF the track has burnt out, you should get no voltage on the black/white from the CDI

when the motor is running

I'd do some tests first to confirm this before experinenting and I'd also check the kill switch especially isnt leaking current to earth as this does happen from time to time

and may be the reason the track failed in the first place.

HTH



EDIT



BE CAREFUL !!!!! the voltages may be in the 200 Volt region so observe due caution and good electrical practise
 

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Discussion Starter · #12 ·
I was out of town for a while and then have been working on my friends CB750 so I haven't had much time for the CX. I reassembled the cooling system and now I need to do the 7v reg it looks like. But I could start it again finally, and tried the other cdi box. That one wouldn't start it. So the first one is back in. It will run on this one. The PO said it didn't have any power above 5000 rpm, so maybe the next group buy on the ignitech might fix both of those issues?
 

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I had this exact problem on my 79 custom when it ran on the CDI. The Ignitech solved the kill switch problem, as stated above, I believe my CDI just had a fault with the kill wire. Cobram still had a few last time I checked in the selling forum.



Regarding the comment on no power, I believe you should check the stator to make sure it is good to solve that. If you are losing power it is likely that one or the other coil is going on the stator.



If you are thinking of getting the ignitech, I'd recommend you change out the stator for a regular non-CDI type, they have more output (250 vs 175 watts) and are supposed to me more durable as they only have the charging windings. That is the route I took and have not looked back since - though, I cannot use a CDI on my bike anymore, which, is not a big deal.



There is also a quick stator bule or white wire fix you can do, but you'd have to look it up in the sticky reference thread in general discussion, b/c I can't remember the particulars, but it might get you going.



Keep in mind your CDI might be fine for a while. It is 30 years old though, and stalling the bike did suck




Mike
 

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Rats, all the CDI schematic stuff is on my other desktop I haven't put back into place in here again but if I recall the kill switch did nothing more than to short out the stator's HV output.
 
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