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CX500 not sparking - Smoking top of Regulator

7096 Views 45 Replies 12 Participants Last post by  marshallf3
just picked up a 79 CX500 with 30k miles on it . I'd like to give a big shout out to all ye CX500 owners ! I've already met alot of you online

has the CDI ignition , things i've checked are . kill switch ok , starter button ok sending voltage to the yellow/red wire to solenoid when i push the start button(new Starter Solenoid coming in mail this ones not working) . when i jump the solenoid she cranks over fine but i get no spark .. shouldnt it be sparking? pulled plug and have it grounded to bike at a good ground. also i have cleaned the ignition coil connections on both coils to make a good ground. so my question is shouldnt it be sparking by jumping the solenoid? These are new NGK plugs .. old one not sparking either. I did also check for voltage at the coil wire connection before coil to see if getting any voltage to it .. nada. oh and i also did check the flywheel through the timing hole on the engine to make sure its turning .. yup its turning.

also i have read about the neutral switch . i do get a neutral light when electric is on . that wouldnt make it not spark would it? also checked the pickup coil continuity o/w wire to lt blue/white wire on the engine side. i also checked for some AC voltage at these wires when cranking by jumping the starter relay and its getting voltage there. Its cranking over fine , i even tried to jump it with my car battery still no spark so not battery related.

something with the CDI or Stator related me thinks ? oh also i did think of something else . i did have the front head light/instrument cluster on but it wasnt all hooked up with the ground. i have left it off unconnected until i paint it .. do i need that on and grounded right for it to spark ? just a thought , seems to me if i'm getting voltage at the starter relay solenoid when i push the start button it should be ok and crank over and spark eh? i have been wrong before tho .. once i think

looking forward to continuing this CX500 resurrection
.. haha any help apprieciated.

what my bad boy looks like now

Pic 1

Pic 2

when i get done with her it will look like this one

Pic 3
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This resistance check on CDI may be revealing Stitch Link , but by all accounts the real test is swapping out with a known good CDI.
Anyone know what voltage we should be getting from CDI to the coils when cranking?

I've been having the same trouble and have followed much the same line of inquiry as you. I'm waiting on a known good CDI. Post back with any findings and I'll do the same.
Where did you get that checklist (web address)?
Just installed an Ignitech (compliments of Cobram), but still no spark. I really thought that I'd put my finger on it too.

Still getting very weak voltage from the CDI to the coils when cranking. The battery is pretty weak and likely needs replaced, but I'm jumping it off my truck. Even still, I'm only reading about 10volts off of the black wire from the ignition key that I spliced the red Ignitech wire into - could my trouble all stem from a weak battery even if I'm jumping it?

Any thoughts on how I might salvage this situation would be much appreciated.

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could be a short in the wiring somewhere too. just a thought.

did you run the tests for the stator coil? and pick up coil?

Did resistance test on the stator coil, but haven't checked voltage on it nor the p/u coil while cranking. I need to get my battery charger back from a buddy and see if I can get a good charge on it. I intend to continue jumping to check voltages so as to not run it down - mistake?
She's up!... sort of. Original CDI was at fault!

Ran through stator and coil tests again. Most of my values were on the high end of spec or just above. I was beginning to come to terms with the likelihood of an engine out scenario and then, on Cobram's advice, I decided to try jumping the bike with battery out in the event that a cell was shorted - I had mentioned that I was getting low voltage to the red wire on the ignitech. Battery out, the red wire was still reading very low. Digging through the posts I found Doward's description of how he used a double bullet connector to patch the red wire into the tail light wire in place of the little splicer the provide with the kit. Bingo! Double checked all my connections, gave it some choke and fired it up. Engine raced at full choke so I backed it way off. Idle is solid, but throttle response is choppy - this I attribute to the fact that I have my spare carbs on there and they're pretty buggy.

Tomorrow I'll run through my good set (they were leaking at the float bowl gasket - float level?) and get them ready to mount this weekend. Then new fluids and cleaning up the exhaust. Its still hitting the 90's here almost every day so i'm not so worried about summer getting away from me yet.
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right on .. good to hear you found the issue. I believe its the CDI on mine too .. i found a guy near me that has a few extra CDI's so tomorrow i am picking one up. now i just wish i had the 90 degree weather ! do they sell that anywhere?

hey what is the red wire you speak of? and what wire on the bike side is this power coming from ? what color wire is it on the original CDI ?

Ironically, most folks around here are complaining about the weather. I try to explain that it only feels unbearably hot if the only time you spend outside is walking from airconditioned house - airconditioned car - airconditioned office.

The red wire is only relevant if you're installing one of the ignitech CDI (new aftermarket). A used oem will plug in just like your old one. On the ignitech the red wire, I believe supplies power to the unit. You splice it in at the brake light bullet (black wire) located near the coil and kill switch connectors.

Good luck with your CDI swap - seems like there's a really good chance that you're in for some near-instant gratification.
I'm happy because at least now i know what the issues are.

I know what you mean. Uncertainty is the devil, but also the source of the best challenges and adventures. Anyhow, I sleep much easier knowing where the issues lie (or, at least, when I think I do).
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