The bike was running just fine about 2 months ago. It would almost always start with little to no trouble and would run fine for the most part. After a series of projects that I've been working on I put everything back together and now I can't get ANYTHING. I'm getting absolutely nothing from the spark plugs... So I replaced them. Still nothing. So I tested the plugs with a continuity tester and wasn't getting anything on the sending side of the coil. So I got new coils. Still nothing... I cranked on it so much that I killed my battery and was using a portable power pack to keep it going. I decided to get my battery checked and it came back as a bad core so I purchased a new battery and still absolutely no spark out of the plugs. Someone told me to run a ground wire from the battery to the block incase it was a grounding issue but that didn't work either. I'm not sure what else to try. the coils are receiving power but I'm not getting anything on the sending side of the coil. Not sure if there is an electrical component that I am missing or something else I could try. Any ideas?
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Won't start... Electrical issue?
- Thread starter jsmith2
- Start date
The wires are just a single wire from the coil to the plug. Unscrew them from the coil and look at the ends. The coil should pierce into the cable to make contact. I think the coil has like a screw inside so the wire needs to spin on and off. Then you can test the wire
Does the bike have points or electronic ignition?
I'm not sure I know what that means... It has an electric starter? I'm sorry I don't know what points are
What year is the bike?
'81 xs400 special
So it'll have electronic ignition. There's a TCI box (Transistor Controlled Ignition) under the battery. Has a big connector into the wiring harness.
Also uses pickup coils to trigger the ignition, which are located under the cover on the left side of the head.
Seems like it may be the spark plug wires.
Do what Damian suggests above. Unscrew the plug wires from the plug caps and from the ignition coils. Check continuity. I'd cut off 1/2" from each end to expose clean wire.
Could have corrosion at the ends.
Also uses pickup coils to trigger the ignition, which are located under the cover on the left side of the head.
Seems like it may be the spark plug wires.
Do what Damian suggests above. Unscrew the plug wires from the plug caps and from the ignition coils. Check continuity. I'd cut off 1/2" from each end to expose clean wire.
Could have corrosion at the ends.
What should the continuity read? Thank you! This helps a lot.
That short of a piece of wire should read 0 ohms end to end.
Coils should read 3 ohms on the primary and 8.6k ohms on the secondary.
Coils should read 3 ohms on the primary and 8.6k ohms on the secondary.
What was a work you did on the bike? Have you looked at your fuse box lately?
Could be the tci box that went bad. None of my bikes have them. They either work, or they dont..
Could be the tci box that went bad. None of my bikes have them. They either work, or they dont..
I basically rewired all the lights. Headlight, brake light, blinkers, added a new switch on the left side and new brakes. I did not mess with the kill switch or anything with the ignition. Previous owner did a LOT of rewiring and did a horrible job at it. He eliminated the fuse box and just added individual fuses on the wires. I checked those and they all looked good. I suppose there's a chance I could have bumped something lose on the wiring but I don't even know where to start with that.
Before I took the bike apart it did somewhat die on me but I assumed it was an issue with the fuel. It just lost power, started spitting for a second and then died like it ran out of gas. I was able to get it started once more for a few minutes after that. I don't know if that has anything to do with this though.
Update: I ran a test wire from the coil to see if I could get a spark on that, nothing. Using my continuity tester I tested the wires going into the pickup coil and only got a signal from 2 out of the 4 wires. Followed them all the way back to the TCI box and tested them there and still nothing. It is the white/red wire and white/green if that says anything. Any ideas on if this is an issue with the pickup coil or the TCI box? both these wires go straight from the pickup to the TCI, nothing else.
Try to test methodically to avoid running in circles.
Did the ignition coils test properly?
In what way did you test the pickup coils?
A continuity test won't give you anything.
A resistance test of the pickup coil should confirm its condition.
There's no specific test to be done directly on any wires coming out of the TCI.
It would be a better idea to check for voltage to the ignition coils on the red/white wires, after also confirming the primary and secondary resistances.
Chances are either the TCI box is bad or the previous owner botched the wiring too much for Internet diagnosis.
Did the ignition coils test properly?
In what way did you test the pickup coils?
A continuity test won't give you anything.
A resistance test of the pickup coil should confirm its condition.
There's no specific test to be done directly on any wires coming out of the TCI.
It would be a better idea to check for voltage to the ignition coils on the red/white wires, after also confirming the primary and secondary resistances.
Chances are either the TCI box is bad or the previous owner botched the wiring too much for Internet diagnosis.
Bare with me, I have no idea what I'm doing here. Sorry! I'm just using a test light to make sure everything has power as there was so much done to existing wires. My test light comes on at the ignition coil, but not at the screw coming out of the coil (I was told this should trigger the light?). I did the same test on the pickup coils with the wires coming out of the connector. All of them light up except the ones I mentioned above. How would I conduct a resistance test on the pickup coil? Is there any way to do a real test to confirm if my TCI box is good or bad? Thanks for your patience and suggestions! Really do appreciate it.
You'll need at least a basic digital multimeter to read resistance values.
Also find a manual that covers your bike .It should have the information you meed to test the coils.
Another recommendation is to pull the spark plug wires off and cut a half an inch off and put the the plugs back on. In my case I tried to just push the plug boot ends back on. But there is a small screw style connector in the plug ends and they had to be screwed back onto the plug wire. Test your coils without the spark plug wire attached. And clean up your wires on both ends. Your wires should pretty much test out at very low resistance conpared to the coils. If they dont and you have resistor cap spark plugs then yoi would need new low resistance wirws. Let us know how your testing goes and if you have any questions along the way.
Here is a video. He doesnt take the wire off. I did in my test .
If the wires are old it wouldnt be a horrible idea to go ahead and change the wires. Just make sure you are getting the correct wires for your spark plugs. If you have standard resistance plugs then yku want low resistance wire.
Another recommendation is to pull the spark plug wires off and cut a half an inch off and put the the plugs back on. In my case I tried to just push the plug boot ends back on. But there is a small screw style connector in the plug ends and they had to be screwed back onto the plug wire. Test your coils without the spark plug wire attached. And clean up your wires on both ends. Your wires should pretty much test out at very low resistance conpared to the coils. If they dont and you have resistor cap spark plugs then yoi would need new low resistance wirws. Let us know how your testing goes and if you have any questions along the way.
Here is a video. He doesnt take the wire off. I did in my test .
If the wires are old it wouldnt be a horrible idea to go ahead and change the wires. Just make sure you are getting the correct wires for your spark plugs. If you have standard resistance plugs then yku want low resistance wire.
