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Discussion Starter · #1 ·
Experts...good news and bad news story. After a complete carb clean and rebuild, it will start up and run, but only with attention to throttle/choke. It won't idle...and the balancing is way off. I've tried adjusting the idle with the screw, and it seems to have no affect.

The left side is definitely running rich as the spark plug is black and it gets much hotter. Also, I set up my home made carb sync gizmo and the right side is sucking waaay more vacuum then the left. I adjusted the carb sync screw clockwise to reduce the right side vacuum as per the manual, but that also seemed to have no affect.

I'm just not sure where to start first...try to get it idling and then work on syncing, or is there something else I should focus on first. Any advice appreciated, thanks.
 

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Usually if it won't idle it means cleaning the carbs again. How did you clean the carbs? Did you remove the slow jet when cleaning?
Another possible problem causing failure to idle would be an air leak somewhere between the carb and the cylinder head. Have you checked for leaks?
 
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Improperly adjusted valves can cause your same problems. This may not be your problem but it is routine to adjust the valves prior to syncing the carbs anyway.
 

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First, what if any mods have you done? do you have the stock airbox or pods? stock exhaust or free flowing? any jet changes? are the valves set correctly?

Assuming your bike is 100% stock and valves are set, I would pull the carbs again. I know, it sucks, but at least it's easier on the CX/GL than on inline 4 bikes.
Verify all passages are clear, including the air cut off valves. the hardest ones are the idle circuits which have 5 (6?) possible outlets.
Are the cutoff valve diaphragms 100% intact, no tiny tears in the center? If any tears, either replace them or block off the passages
Confirm the idle mixture screws are set 2-2.5 turns out and have orings and washers in proper position
Manually/visually sync the carbs. Use the idle set screw to have the butterfly come just barely off the body. Make sure this is the same for both carbs. Adjust until both butterfly valves are in same position relative to reference holes, shown in pic. This is usually pretty close to sync'd and visual inspection is easier than vacuum inspection. The home made rigs can be super sensitive.
Verify float height, measuring when the float are barely engaging the valves. Don't simply turn the carbs upside down, it will be wrong.
Set the idle screw to just barely engaging. That will be the minimum idle setting and you will then only need to gradually tighten the screw to raise the idle.
Re-mount the carbs and try again.
207887
 

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Discussion Starter · #5 ·
Thanks for all the feedback... I was hoping a good clean and replace would be good enough, but I will inspect the valves and pull the carbs again.

To answer the other questions:

1. Still using stock air box, but eliminated the H-box for a free flowing exhaust.
2. No jet changes...just took it all apart and gave everything a good cleaning. (it was in remarkably good shape)
3. I have not checked for air leaks yet...one more thing to add to the list. I'll do that for fun before I remove the carbs.

Fuel injection rocks...
 

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'84 CX650E that is evolving into a GL500
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What prompted you to clean the carbs? Was it doing the same thing before you cleaned them or is this new since cleaning them?

What did you use for reference while cleaning the carbs? There are 2 good books on cleaning and setting up these carbs, Larry's Carb Book and the one by Mike Nixon and there is some good information in the FSM that is good enough of nothing is too badly wrong with them to start with.

How far apart did you have them for cleaning? If you separated them you may have assembled the balance adjuster's parts in the wrong order, which would change the balance significantly even if you didn't move the balance screw.
For that matter, if you turned the balance screw at all while working on the carbs it could result in the condition you describe.

BTW: Fuel injection can still have problems if a passage becomes clogged with varnish or there is an air leak.
 

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Discussion Starter · #7 ·
When I started the bike for the first time, the carbs were leaking and it was not running well. It would idle but not rev up. Since I was taking the entire bike to pieces anyway, I followed the FSM to completely separate and disassemble the carbs for cleaning (and I replaced all the rubber and the valves). Leaks were all fixed and I thought I put it all back together correctly, but might have made a mistake...only real PITA was that winding spring for the choke. I definitely messed with the balance screw while putting it all back together.

Did a leak test today by spraying starter fluid at the junctions from the head all the way back to the air box on both sides and it looked ok...no rev increase, but I had to hold the throttle at approx 2k revs cuz it does not idle well. Right side is running crazy hot compared to the left. I'll adjust the valves next weekend and check again before pulling the carbs.
 

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That makes sense. Whenever you have the carbs apart you should expect to hook up the vacuum gauges and balance then afterward.
The valve clearances would have to be really, really out of spec to affect the way it runs that much but it is always a good idea to check the valve clearances before balancing the carbs.
BTW: If you do the camchain tensioner adjustment while you are checking the valve clearances it adds about 10 seconds to checking the valves.
 

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From Bob's earlier message "If you separated them you may have assembled the balance adjuster's parts in the wrong order, which would change the balance significantly even if you didn't move the balance screw."

This may be the culprit. You can check it without removing the carbs, but they will need to come off to fix it. Here a pic for reference, assuming mine are correct ;)
207897
 

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Yours is assembled correctly.

If dprannos is incorrectly assembled this can be remedied without splitting the carbs.

Possibly without removing them if you hold your mouth right.
 

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Discussion Starter · #11 ·
Yup, mine is wrong...spring is underneath. I'll need my "Honey I Shrunk the Kids" machine to fix that without removing the carbs. Thanks to all for the help.
 

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Discussion Starter · #13 ·
First, what if any mods have you done? do you have the stock airbox or pods? stock exhaust or free flowing? any jet changes? are the valves set correctly?

Assuming your bike is 100% stock and valves are set, I would pull the carbs again. I know, it sucks, but at least it's easier on the CX/GL than on inline 4 bikes.
Verify all passages are clear, including the air cut off valves. the hardest ones are the idle circuits which have 5 (6?) possible outlets.
Are the cutoff valve diaphragms 100% intact, no tiny tears in the center? If any tears, either replace them or block off the passages
Confirm the idle mixture screws are set 2-2.5 turns out and have orings and washers in proper position
Manually/visually sync the carbs. Use the idle set screw to have the butterfly come just barely off the body. Make sure this is the same for both carbs. Adjust until both butterfly valves are in same position relative to reference holes, shown in pic. This is usually pretty close to sync'd and visual inspection is easier than vacuum inspection. The home made rigs can be super sensitive.
Verify float height, measuring when the float are barely engaging the valves. Don't simply turn the carbs upside down, it will be wrong.
Set the idle screw to just barely engaging. That will be the minimum idle setting and you will then only need to gradually tighten the screw to raise the idle.
Re-mount the carbs and try again.
View attachment 207887
UPDATE - Pulled the carbs and fixed the sync screw, then adjusted everything as recommended above. Put it all back together, started it up and immediately noticed cold exhaust from the left side. Checked for spark on the left and there was none (I am assuming there was spark last time because the left head was hot and blowing hot exhaust too). So I checked spark on right side and it was good.

Decided to swap the yellow and pink bullet connectors for the coils and all sparks are gone. Swapped the coil wires back to normal and no spark anywhere. I'm getting a bad feeling about the coils. Are there any electrical test I can do to confirm it is the coils?
 

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UPDATE - Pulled the carbs and fixed the sync screw, then adjusted everything as recommended above. Put it all back together, started it up and immediately noticed cold exhaust from the left side. Checked for spark on the left and there was none (I am assuming there was spark last time because the left head was hot and blowing hot exhaust too). So I checked spark on right side and it was good.

Decided to swap the yellow and pink bullet connectors for the coils and all sparks are gone. Swapped the coil wires back to normal and no spark anywhere. I'm getting a bad feeling about the coils. Are there any electrical test I can do to confirm it is the coils?
There is a black wire that needs to be connected too. Or else you won't get any spark. I belive theres an ohm resistance reading or you can check for a spike in volts by grounding your multi meter positive to the inside of the ignition coil cap that attatches to the spark plug, and the ground lead on the engine or any bare metal part. If there's is no spike in voltage when cranking over the bike the coil is most likely bad. If you don't then move the positive side to the pink and yellow wire and see if you do. If you do then the coils are bad.
 

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I have half a dozen multimeters and I wouldn't connect any of them to the spark plug cap to look for pulses that are over 10,000V.......

I'm not familiar enough with the CDI coils to tell you how to test them. Hopefully someone who does know will be along shortly.

One more thought: How are you checking for spark? The plugs won't spark of you lay them against the valve covers because the valve covers are rubber mounted so they aren't grounded. The bolts that attach the covers are grounded so if you lay the spark plugs against them they should spark.
 

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Discussion Starter · #16 ·
I have half a dozen multimeters and I wouldn't connect any of them to the spark plug cap to look for pulses that are over 10,000V.......

I'm not familiar enough with the CDI coils to tell you how to test them. Hopefully someone who does know will be along shortly.

One more thought: How are you checking for spark? The plugs won't spark of you lay them against the valve covers because the valve covers are rubber mounted so they aren't grounded. The bolts that attach the covers are grounded so if you lay the spark plugs against them they should spark.
I have been using the bolts for the hangers...worked the first time I checked spark. Hoping this is all operator error.
 

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Discussion Starter · #18 ·
Spark is definitely intermittent now...even saw a faint spark on the left side very briefly last night. I have read about different replacement coils that can be used, but the posts were pretty old. Can you recommend a replacement option for the coils?
 

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Have you checked the other parts of the ignition system:stator, pickups and pulsers, plug wires and caps?
 

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Discussion Starter · #20 ·
I have not...was assuming the coils were the most likely cause, Do you have a quick guide to check the rest of the system?
 
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