Greenhorn newbie with electrical issues

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darkside

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Hey all, this is long over due. I've been a member for several years but haven't properly introduced my self. I have an 81 xs 400 special II . She sat for a year after a year of riding. I don't know shit about bikes but I'm pretty inclined mechanically.
Anyways, the bike won't start right now and via process of elimination I think my problem may be with the cdi module. I ordered a new part and will put it in as soon as possible. Is there any way to put a multi meter to it and check the resistance ?
Here's a pic of the old girl, I have dubbed it the Yama-hee-haw, since its a cross breed of a cafe / bobber/ tracker. Thanks
 

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Unless you've put on a good CDI and it works, I can practically guarantee you that the CDI is not the problem. When I thought my CDI was bad, it was a bad ignition coil. Another thing that can go wrong is loose or corroded connections. You can pull the copper blades out of the connectors and clean them one by one to restore continuity. Just make sure to put the connectors back properly and securely.

Or, it may be that you're just not flowing gasoline. Have you visually inspected for spark at the plugs?

I don't mean to come across rude, but I always have to force myself to check obvious things first instead of jumping to conclusions about what is causing the problem. If you can provide a little more info about your troubleshooting process this forum will get your bike going in no time.
 
Sorry to cut the story short . My bike died on me while I was at work about a year an a half ago, I spent the last year checking all I knew how. The gas was good and flowing freely, the battery was charged and holding. I put in new plugs and fuses and the coils both checked out good.
Four months prior I put in a new regulator and the rectifier checked out fine. I also checked to make sure I had spark. That test proved negative. All I think I'm left with is the cdi, and I don't know anything about it. Any insight would be appreciated and feel free to harass me as much as you feel fit, I dish it out just as well.
Thanks
 
can you borrow another TCI just to check?

there is really no alternative unless you know an electronics engineer with the proper equipment. We have Re'x speedshop in the UK who can repair TCI's
 
By "coils are good" do you mean the resistance is within spec? Or do you mean you have 12V at the coils?
 
My friend check the resistance on the coils last fall, as far as I knew they both checked out fine. Last night I was trying to re check them and I found out that I had no power going to the coils, and obviously no spark to boot. I still have plenty of compression and the battery's pushing 12v, the lights work and the starter fires.
I'm at my wits end, any help would be very much appreciated
 
This is good news! If there is no power at the coils (and your battery is still charged and your fuses are good) we can trace the problem back from there. I don't have a wiring diagram, but there are several on this site or you can look in your shop manual.

On the diagram, follow the wires that go into the coils back to the next component. Check for voltage there or anything amiss. When you find voltage you know the problem is probably between that point (where the voltage is) and your coils (where the voltage isn't).
 
So the contacts in the ignition switch could be dirty, preventing voltage from reaching the coils, or the connectors need to be cleaned. Or the problem could be happening before power even gets to the switch.
 
You do have the Engine Stop Switch in the "ON" or "RUN" position don't you? You wouldn't be the first person to overlook that. :doh:

It could also be another source of your lack of power problem if the switch or its connections are bad.
 
The switch is most definitely in the on or run setting. I'm going to go through and visually check for bad , broken, or frayed wires as soon as possible. Also I will work backwards from the coils and check for power at all stops along the way.
 
The switch is most definitely in the on or run setting. I'm going to go through and visually check for bad , broken, or frayed wires as soon as possible. Also I will work backwards from the coils and check for power at all stops along the way.
 
Is checking the ignition switch as easy as just crossing the wires that go into it, and then checking for spark? Or is there a better or simpler way to do it?
 
With the switch in the "on" position, you should have continuity between all three wires into the switch. So just unplug the switch from the rest of the harness and check continuity between the connector ends.

While you're unplugged from the harness, check for voltage at the brown wire, which comes directly from the fuse box. If you don't find voltage there, checking the fuse box is the next step. Keep in mind with the old style fuses even a hair-line crack can make the fuse useless but be very hard to detect visually.
 
No progress to speak of yet. I started to go through all the wireing looking for frays or burns or anything of that nature. I am currently trying to teach my self how to use a voltage meter . I'm a carpenter by trade so my electrical knowledge is limited, still I know that it has to follow a path. And I know that if I keep at it I should be able to figure it out with the help of all you guys here on the forum.
Thanks for all the help this far and for all the help I may get in the future.
I wish I had more time to spend on it, but being a single dad and working 55 hrs a week kinda puts a crimp on my time.
 
I was thinking that maybe he could try to hotwire the coils like a car thief would back in the olden days. I can't see how, but does anyone here know if this would create an issue with the CDI? (No, I never stole a car but I came from the era where every teenager knew how to hotwire a car.):wink2:

One other piece of advice; Since you seem to understand the concept of an electrical path be aware that most people get so hung up on finding where the power is coming from or going to they forget that it has to get out to complete the path. In other words, don't assume any of your grounds are good. They are probably the quickest and easiest thing to check in the first place but often the most overlooked. I have seen over the years countless people spending hours trying to correct an electrical problem that turned out to be a loose ground wire or two parts not tight enough to complete the circuit.

Good luck, it may seem daunting right now but there is a solution, you just have to find it.
 
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