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Discussion Starter · #1 · a moment ago

Hi everyone, I recently bought a cx500 custom and I'm not getting spark, I tested the coils and some of the cords that come out of the cdi and they get power, I tried testing the plug ins for the coils and has no power, the spark plugs caps didn't get power threw them but when I tested the coils with them off it got power so I used a cap that I knew worked and still nothing, I disconnected the Killswitch as well, the regulator lights and cyclinoid get power, only thing I haven't tried is a new battery, could that be causing no spark? Any help would be appreciated I spent all my money on this bike and got ripped off
 

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A 1982 cx500 in the USA “should” be TAI, not CDI. The TAI kill sw circuit provides power to the ignition system, opening to STOP when pressed, the opposite of a CDI system in which the kill sw CLOSES when pressed to STOP. Disconnecting the kill sw (as you say you have done) on your TAI system will ensure there is no spark. First determine whether you have the stock TAI (expect a pair of NEC aluminum looking ignition modules under the seat I think on CX500) or the larger single smooth steel box of a CDI ( also under the seat). Troubleshooting is not the same. The TAI system is generally considered robust and the two sparks are mostly independent, meaning it is unlikely both sparks die together. More common “dual failure”causes are loss of power thru the key/kill sw circuit, weak battery, bad grounding or open fuse. A “dual failure” on a TAI system with an unmodified wiring system is relatively straightforward to troubleshoot and fix.
 

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Discussion Starter · #3 ·
A 1982 cx500 in the USA “should” be TAI, not CDI. The TAI kill sw circuit provides power to the ignition system, opening to STOP when pressed, the opposite of a CDI system in which the kill sw CLOSES when pressed to STOP. Disconnecting the kill sw (as you say you have done) on your TAI system will ensure there is no spark. First determine whether you have the stock TAI (expect a pair of NEC aluminum looking ignition modules under the seat I think on CX500) or the larger single smooth steel box of a CDI ( also under the seat). Troubleshooting is not the same. The TAI system is generally considered robust and the two sparks are mostly independent, meaning it is unlikely both sparks die together. More common “dual failure”causes are loss of power thru the key/kill sw circuit, weak battery, bad grounding or open fuse. A “dual failure” on a TAI system with an unmodified wiring system is relatively straightforward to troubleshoot and fix.
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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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That's not an '82, though it could have been mis-titled if it had sat in dealer inventory from the previous year. What does the label on the steering head say?
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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Does that number match what's stamped into the other side of the head tube?
If so, someone converted it to the older system, or maybe rebuilt their older bike on the '82 frame.
If not, someone just swapped the VIN plate (= title fraud).
Let's hope it's the former.
 

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The engine serial number would tell if there had been a swap to an earlier CDI engine.
 
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