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Discussion Starter · #1 ·
Hey everyone,

New user and new to motorcycles. I've been working on my 1980 CX500c for a while trying to get it running. I saw it ride 2 years ago when I bought it but It hasn't worked since. As I've gathered from most troubleshooting forums, the carbs are the issue. So I got myself a Carb Rebuild Kit and just sort of replaced the pieces (gaskets, needles and jets). I inspected for cracks but when it ran it had no gas leaks in the float bowl. I also soaked the pieces in carb cleaner for 24 hours and the metal components seem very clean (a SMALL amount of spottiness, but nothing bad). I reassembled them and put them back in the bike.

Still isn't starting. It electrically turns over, but I'm not sure what the issue is... when I open the float bowl release gas comes out of both floats, so I know gas is getting to the carbs. There is a minor tear in one of the booties but between tape and carb clamps I feel like its sealed. Maybe there's air leaks? Maybe the carbs are being flooded with gas (don't really understand what this means), or maybe the rebuilt was done incorrectly.

I've also changed the coolant reservoir, bought and charged a new battery, installed new spark plugs, installed new front brake pads, rebuilt the master cylinder and installed new taillight and turn signals.

Please help me!

Thanks guys!



1980 Honda CX500c - Brat
 

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Discussion Starter · #4 ·
I replaces the spark plugs on both sides, but snapped off one of the cover screws inside when putting the header cover back on. Maybe its creating a vacuum issue with 1 of the 2 screws basically not there?

Thanks for the comment! I appreciate it
 

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A $2 harbor freight spark tester light is a simple way to see if you have spark at each cylinder when cranking. Also did you spuirt out all the carburetor passages with carb cleaner?

Good luck!
 

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Spark plugs don't initiate spark...that's why he asked if you have tested to see if there is spark at the plug; It could be your ignition (stator,wires,etc.) are bad. Go to youtube and see how to test for spark on an engine.
 

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Discussion Starter · #8 ·
Ok great! Thanks everyone! I'll test that out tonight!

Now say I test it and it works and I'm getting spark from the new plugs. What would be the next area to check??
 

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The snapped valve cover bolt will also cause a terrible oil leak, even when the engine is only idling, after you get it started . Better fix it out right.
 
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Discussion Starter · #10 ·
Ok will do! Does anyone know were or what to ask for when trying to replace bolts? Does Home Depot's mechanical bolts work? or are all these threads specific for mechanics work?
 

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Take off the valve cover. If the broken screw can be turned with vice grips it should come out easy. If it broke off flush you can use a dremel tool with a grinding disk to cut a slot in it then take it out with a screwdriver. If it is below flush you will need to drill a hole in the stud and use a "easy out" to remove it.
 

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Ok will do! Does anyone know were or what to ask for when trying to replace bolts? Does Home Depot's mechanical bolts work? or are all these threads specific for mechanics work?
Best go here CXGL and read the Factory service manual for your bike. Learn how to research on the search function. Ask questions after researching topics and learn to post pictures to help explain what issues you have. Good luck and welcome
 

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Can we assume you took the top covers off the carbs before soaking them in carb cleaner? I do hope you did. Because if you didn't take those parts off that are under that shiney cover, you are screwed. It sounds to me like you need some experienced help, to fix the carb and broken bolt issue. That bolt is listed as "obsolete" so you will need to reach out to the members of this forum for that item. Don't torque these things like you are working on a farm tractor.
 

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Discussion Starter · #15 ·
Ok so, if the spark plugs don't work I'll get new plugs, if they still don't work I need to follow it back to the ignition coils or battery. If they do work then it has to be a fuel (carb) issue.

What are some of the potential issues if the carbs are clean and its still not firing up? engine is flooded? Starter is toast? Air Leakage?

You tell me. Thanks!
 

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Just a couple of thoughts for you....XB

Do you have any manuals? I'm gonna guess that you don't. Please access the WIKI to download the FSM (Factory Service Manual), then begin reading it.

Second, you will want Larry Cargill's book about these carbs, just buy it. Sooner or later you will need it.

Third, get a copy of either a Haynes or Clymers manual. These are only guides for steps not detailed in the FSM. Remember, the FSM was written for Honda mechanics. Any differences in specs or procedure the FSM is the authority. One handy item about these manuals is the colored wiring diagram. Very important when electrical issues surface.

Slow down. Do the diagnosis first, narrow the problem, then repair.
 
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