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Discussion Starter · #1 ·
Good day, folks. I have been a lurker to this valuable forum for some time now. Today, I have registered with a question of my own.



I have bought (cheap) and been working on a '79 CX500 that has apparently not run for several years, and shows signs of having been partially submerged. Using tips from this forum, I actually got it running last weekend for a couple of minutes with the yellow stator leads disconnected. I have not been able to get it to start since then. I want to get the machine to start before I pull the engine for a CX triple bypass.



Today, I fully charged the battery, checked the fuses, and pulled the plugs to see if I was getting any spark. I am getting no spark on either side. Put on new plug caps, same thing. Disconnected the black-with-white-stripe kill switch lead, no difference. Pulled and cleaned the coil leads to the CDI unit, no change. Pulled the yellow stator leads, nyet.



Since the bike ran a week ago even if for a few minutes, I think I can assume the coils are okay. That leads me to the CDI unit. I have suspicion that this unit was from a salvage yard since it has a grease pencil marking saying "CX500". Can anyone give me some simple tests to verify my thought that the CDI is bad?



If it is bad, can you provide counsel on where to get a replacement? I just checked e-bay with no luck. I am open to suggestions.



Thanks for all of the help from the forum thus far, and thanks for the counsel on this CDI unit.



Regards.
 

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Have you checked all the connections to be sure there is no corrosion keeping them from making contact? Dip them in full strength CLR. It cleans them up nicely. Make sure all the female ends are crimped down too so they make good contact.



The ignition switch contacts could also give you a problem. Make sure you have good power coming from it.
 

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Put your location in the user info or sig line. There might be a lister nearby who can help you by doing a quick CDI swap with a known good unit. That's the quickest method that leaves no doubts about it's integrity. Check the links in the Blindstich's Quick Reference
 

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Discussion Starter · #4 ·
Thank ou for teh replies thus far.



Larry, I'm a fan, bought your carb book. Could you be a bit more specific as to connections I may want to check? I am open to instruction.



I live in Dallas, so hope someone can offer help.



Thanks again.
 

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All the connections under the seat are CDI and stator related. Check, clean and tighten all of them. Also, on the left side above the air cleaner inlet are bullet connectors. The yellow and pink go to the coils. Blk/white goes to the kill switch from the CDI unit. Light green w/red strip is neutral switch. Black & green w/yellow strip is for the rear brake switch. Obviously the coil wires are important to check and clean, but they all should be done as well as any and every connection through out the bike. The other ares to check are all the grounds. Even the base of the coils need to have a good contact with the frames bare metal surface.



Next to the battery, under the starter solenoid is 2 red and 1 white multi plug connections. These are also important to the charging system. Do the same with these as well.



When everything is clean and has proper contact, you have a better chance of isolating, if not eliminating electrical issues.



The other possibility is a broken wire somewhere inside the harness. A multimeter set to continuity test can establish weather you have an open circuit as well as the recommended voltage or resistance for that wire or circuit. A good shop manual will help in that area.



WHen all the connections are cleaned and serviced I use a bit of Di-Electric grease in each connection to keep them from corroding in the future.
 
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