250SX ignition problem

[PAtrikerguy]

I recently purchased a 85 250SX and having trouble with the ignition. It starts and runs fine until you (try) shut it off, it still remains running the only way to shut it off is to disconnect the plug wire. The kill switch on the handle bar is seems OK there is no corrosion of any kind and the key works too because when the key is turned off the lights will shut off. Which leads me to believe that the ignition box (black box) could be bad. Can someone tell me if I am on the right track or not?

[Wickedfinger]

... no, its probably just your ignition switch. Take it apart, clean out any dirt and spider webs, clean up the contacts then try it. If that dosnt work, you probably have a broken wire somewhere. BTW, where in PA do you ride?

[Howdy]

I recently purchased a 85 250SX and having trouble with the ignition. It starts and runs fine until you (try) shut it off, it still remains running the only way to shut it off is to disconnect the plug wire. The kill switch on the handle bar is seems OK there is no corrosion of any kind and the key works too because when the key is turned off the lights will shut off. Which leads me to believe that the ignition box (black box) could be bad. Can someone tell me if I am on the right track or not?

I don't have my book here. So this is off the top of my head. I hope it helps:
If the motor runs good you can pretty much rule out the CDI being bad.

The key switch has 2 circuits. One is used for the Power. The other is used to the kill motor. Look behind the headlight assembly for a black with white stripped wire. Make sure it is connected. That wire when hooked to the green one will shut the motor off. Start the motor and touch the tip of the black with white striped wire to the triple tree. If the motor dies you have a good wiring harness. If it don't die then you probably have a bad wire and will need to fix it.

I have seen many switches get dirty and quit working. Very rarely both switches at the same time though. But still this may be the case also. If you find the switchs to be the problem, you can take then apart carefully and clean them. I have done it quite a few times on different machines.

Let us know if this helps.

Howdy

[PAtrikerguy]

wickedfinger, I live close to Pittsburgh but ride on an hour north at my camp close to clarion.

I will have to go home and try your suggestion. Thanks. I will let you know how it comes out.

PAtrikerguy

[ATCnut]

I agree with Howdy

I am looking at my sx wiring diagram, and both the key switch, and the Kill switch on the left handlebar cluster stop the motor by grounding the black with a white stripe wire. Each switch is connected to ground by a green wire. Because Both switches do not work, I would suspect that the Black with a white stripe wire is broked between the front of the trike and the CDI unit. Check for continuity from the wire on the back of the key switch to the wire in the plug for the CDI.

[PAtrikerguy]

Found a broken (corroded) wire on back of the key cylinder. Also it was a black wire with a white stripe. Thanks for the help everybody.

PAtrikerguy

[Howdy]

Found a broken (corroded) wire on back of the key cylinder. Also it was a black wire with a white stripe. Thanks for the help everybody.

PAtrikerguy

Sweet, At least your able to repair it real cheap!! If you need more help we are here. ;)
Howdy

[MPDano]

Nice thread. Helped me in figuring out my same issue.