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Discussion Starter · #1 ·
1981 Honda CX500c 14K Out cruising down the road today and at about 45 mph. The bike lost power and then just stopped. Felt like it ran out of gas, but has gas. No spark. Anyone have an idea??
 

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1981 Honda CX500c 14K Out cruising down the road today and at about 45 mph. The bike lost power and then just stopped. Felt like it ran out of gas, but has gas. No spark. Anyone have an idea??
jack,confirm the obvious,kill switch set to run.main fuse is ok.does it turn over.do the lights work.
 

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What bandit said, but the most likely culprit is the CDI box. Add your location, there may be a board lister nearby with a spare CDI you can swap out. It's the easiest and best way to check it.
 

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Discussion Starter · #4 ·
Took kill switch apart. Not the problem. Bike turns over well and all lights work. If I let it sit for a while it will fire up for a second or two. Just starts to run. Getting gas to the carbs. Sprayed starting fluid in one cylinder, and not a thing. I am in melbourne Beach, Fl.

Just got it off the road and home. Where can you buy a cdi for this bike
 

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ok,jack.im not qualified to go down the cdi road.

confirm a good spark on each side.plugs,age and colour?
 

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There are several folks on this list from FL, I don't know if they're close by though, that's a big state. A quick swap with a known good one will give you a big data point, it might not be the CDI even though that's usually how they fail.



I have a group buy for the new ones from Ignitech, if you look in the buying/selling you'll see posts on them. But it'll be a while before they come in.



Buying an OEM used one is a crap shoot, these things just up and fail without much rhyme or reason, but that might be your only option to get back on the road asap.



I'd offer you the Ignitech on my bike until they come in...but, the garage I have my bike in has a 12 foot pile of snow/ice in front of. I ain't getting there till at least May.
 

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Remember the kill switch is wired in parallel with the ignition switch, that is how the motor turns off. Isolate the kill switch wire where it plugs in to the CDI and check to be sure it is not going to ground when you wiggle the key. It could be corrosion in the ignition switch.
 

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Discussion Starter · #9 ·
Unpluged the kill switch wire to the cdi, and still no spark. Plugged wire back in and now the bike starts right up. Somthing is wrong some where. It has run for ten minutes so far. I never did understand electric wiring systems.
 

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Unpluged the kill switch wire to the cdi, and still no spark. Plugged wire back in and now the bike starts right up. Somthing is wrong some where. It has run for ten minutes so far. I never did understand electric wiring systems.
my mum[god bless her]used to say....have you washed behind your ears?.

go through all the relevant connections ,clean,dioelectric grease.

some of those connections have not been done in 30 years.

easy/cheap things first
 

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Discussion Starter · #12 ·
The ground from the cdi was loose and a bit rusty. I live near the beach. Does anyone know how to stop the salt air from destroying every wire on the bike.

You guys really saved the day today

Thanks Ken

Jack is really the dog, my copilot
 

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Clean all connections, apply dielectric grease and if needed a waterproof tape like this:

3M #2242 or 06147.

And don't ignore that ignition switch, there could be intermittent problems there from corrosion that could leave you in tennis shoe mode. (walking)
 

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In your conditions(and anyone for that matter) this is the best stuff around,



http://www.aircraftspruce.com/catalog/cspages/acf50.php











My bikes are left out in all weathers and corrosion is minimal once some of this has been applied.Seems expensive but goes a long long way so worth every penny.One Aerosol lasts me a good couple of years on everything including car door hinges,locks,electrics and around the house etc

was developed as an anti-corrosion blocking system for aircraft and is still used in my trade






Testimonials and more info,



http://www.bikeradar.com/gear/categ...nt/product/acf-50-anti-corrosion-formula-9086
 

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Discussion Starter · #16 ·
I put almost 100 miles on the bike and it ran fine. Now it just died again. No spark for awhile after an hour I get spark in right side and bike tries to run. Any ideas??? Coils overheating or wires? Where do I go from here?

Thanks Ken
 

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While not a common failure mode, the CDI can fail intermittent, but it is very, very rare for it to fail like that. Before mine died for good, it made for hard starting when the bike was hot, I chalked it up to the carbs at the time.



Since you're not getting spark on both sides, you can rule out bad coils, they never fail together like you describe.



Could be a short in the stator manifesting itself when engine temps are higher. Pulsor might be failing, this is also very, very rare, but it does happen. A CX'er on this list had a pulsor go south on his bike couple months ago, I don't recall if he was getting an intermittent spark. If you're reading this Doward, chime in with your BTDT.



Re-visit the connectors, clean check them again, gently pulling on the individual wires, sometimes they get squirrely where the butt connector attached to the wire.



Intermittent problems can be a real PITA to figure out sometimes.
 

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Mine died like that and then it seemed like the spark was off. Got it started and the bike ran horrible. Just barely. Let it sit cold all night and it fired right up. 15 minutes in it went odd again. Swapped out the cdi and no problems. That was when I said the ignitech is for me.
 

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Discussion Starter · #19 ·
Back again. I have good spark on the right side. No spark on the lest. Is there a test I can do on the coils? Maybe they are breaking down when thay get hot. Would a bad cdi just have spark on one side? How do I sign up to buy one of the new cdi replacements?

Thanks Ken
 

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