Ignition keeps firing

ejdirin · Posted: September 17, 2009, 9:35 pm Post subject: Ignition keeps firing

Hey guys,

Sorry if the answer to this has been posted elsewhere...

I wired up my chopper project using a generic car key switch from an auto store. I eliminated the kill switch and starter button because the bike would fire up with a turn of the key. The key start has 4 posts: battery, ign, aux and starter. They all work appropriately. When the key is in the on position, the ign reads 13v. When its in the off position, it reads 0v. I should mention this is when the bike isn't running. I haven't tested it while it was running.

The other night I had it fired up to adjust the timing. When I was done, I turned the key to the off position, but the motor kept running. It eventually turned off on its own (likely because I have to tune the carbs). The plugs didn't look like it was diesling.

So I tried it again and this time I pulled the 10amp fuse off the ignition line, essentially using it as a kill switch. The bike shut right off...

Is there any reason why the bike wouldn't shut down when I switched the key to the off position? This must be the reason why every simplified wiring diagram has a kill switch on the ignition wire. It must be there out of necessity....not just for safety.

Thanks in advance for the help!

acbanks · Posted: September 17, 2009, 11:50 pm Post subject: Re: Ignition keeps firing

It's running off the alternator. Yup, you need a kill switch on the ignition line.

pamcopete · Posted: September 18, 2009, 6:01 am Post subject: Re: Ignition keeps firing

ejdirin,

Well, it sounds like you have wired the output from the rectifier to the load side of the ignition switch so that once the engine starts, everything is running off of the alternator. In other words, the only thing you are disconnecting when you turn the ignition switch off is the battery, which means that the regulator is unstable and the alternator will produce a high voltage which, if you have an electronic ignition system, will eventually fry it.

So, you don't need a kill switch if you don't want one, but you have to wire the output of the rectifiers to the battery side of the ignition switch so that both the battery and the alternator are disconnected when you turn the switch off.

ejdirin · Posted: September 18, 2009, 2:04 pm Post subject: Re: Ignition keeps firing

pamcopete,

y motor is a 79 and I modified an 81 reg/rect using the nylon screw technique that you're familiar with shown here:

www.youtube.com/watch?v=i8mnmH59Azc

I'm not sure if it was working correctly because, when I hooked the red and brown from the reg/rect and the black wire from the brush to the 12v, the battery drained overnight to 2v. So, to avoid that, I switched the reg/rect to the ign post so it would be live only when the key was in the on position. This apparently was a bad thing to do.

I'm also running your pamco system with the "big green monster" coil from mikexs. I definitely don't want to burn any of those out.

So I guess I just ignored the initial battery drainage problem by switching the post to ign. Any idea why the battery drained? I don't know if its important, but I used the stock black wire that was hooked up to the brush (like in the above video) rather then running a completely new wire like xsleo suggested in a previous post.

So basically I had the black wire from the brush and the red and brown wires from the reg/rect going to the battery. Is that correct?

Thanks!

pamcopete · Posted: September 18, 2009, 2:38 pm Post subject: Re: Ignition keeps firing

ejdirin,

Well, you need to split the red and brown wires. The red from the reg / rect goes to the battery. The brown from the reg / rect and and black wire to the isolated brush goes to the other side of the ignition switch. If you had the brown wired to the battery, then it would be drawing current for the rotor and run the battery down. So, you were correct when you moved the red and black to the off side of the ignition switch.....but you should have left the red wire connected to the battery.

pamcopete · Posted: September 18, 2009, 2:44 pm Post subject: Re: Ignition keeps firing

pamcopete wrote:

ejdirin,

Well, you need to split the red and brown wires. The red from the reg / rect goes to the battery. The brown from the reg / rect and and black wire to the isolated brush goes to the other side of the ignition switch. If you had the brown wired to the battery, then it would be drawing current for the rotor and run the battery down. So, you were correct when you moved the brown and black to the off side of the ignition switch.....but you should have left the red wire connected to the battery.

Can't seem be able to edit the previous: Should read "you were correct when you moved the brown and black to the off side of the switch...."

ejdirin · Posted: September 18, 2009, 4:35 pm Post subject: Re: Ignition keeps firing

Ok. I moved the red to the battery post on the key with a 10amp fuse in line. Kept the switched brush and brown on the ign post. I'll let that sit for a while and keep an eye on the voltage. I'll give it a test run to see if it shuts off with the key in the morning.

Thanks again for bailing me out....the devil is always in the details....

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