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Discussion Starter · #1 ·
Alright got Larrys Carb book and followed the process. Did buy a carb rebuild kit with new jets and all. Was not able to sync carbs and that might be the problem just wanted someone with more knowledge to chime in. Sorry for the quality of the video. History of the bike it was stored in a barn in northern virginia for 20 or so years. Only has 2500 miles, there are a few bolts missing on the engine mounts so I dont know if the bike was having issues before it was parked but the seller SAYS NOTHING WAS WRONG WITH IT WHEN PARKED. Tried doing the easy pine-sol carb clean but was not getting the right side to kick in untill 5000 plus. Now it will at least run when the left plug is pulled but not as strong. Lots of poping and backfire when engine revved. I am just learning to work on engines so any help would be much appreciated. Thanks

 

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Alright got Larrys Carb book and followed the process. Did buy a carb rebuild kit with new jets and all. Was not able to sync carbs and that might be the problem just wanted someone with more knowledge to chime in. Sorry for the quality of the video. History of the bike it was stored in a barn in northern virginia for 20 or so years. Only has 2500 miles, there are a few bolts missing on the engine mounts so I dont know if the bike was having issues before it was parked but the seller SAYS NOTHING WAS WRONG WITH IT WHEN PARKED. Tried doing the easy pine-sol carb clean but was not getting the right side to kick in untill 5000 plus. Now it will at least run when the left plug is pulled but not as strong. Lots of poping and backfire when engine revved. I am just learning to work on engines so any help would be much appreciated. Thanks





You said you were not able to synch the carbs, do you mean on the bench on on the bike?



Also, if you are getting backfires, I believe there are rubber plugs to prevent that, they apparently are easy to destroy with carb cleaning solutions, so you might check that they are still there.



Mike
 

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I'd say one of your jets is still plugged

sounds like it is running sporadically on the rhs cylinder



check your fuel bowl and make sure your are getting flow through there first..



if plenty of fuel - I would look for a plugged jet..
 

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Discussion Starter · #4 ·
Gotta love this forum fast response. I did bench sync using the steel flat ruller and I bought new rubber plug and they were tight fitting. The right carb is getting plenty of fuel. I ran a little seafoam through the carb and when revving it up I had flames shoot out the exhaust. Is there anything else it could be other than the jets? engine wise or is it carbs for sure. Taking the carbs off is not one of the most enjoyable jobs. Now if anyone can give me a trick for easy on and offs that would be great.
 

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Undo the bolts that hold the inlets to the heads - then twist them carefully away from the heads - remove the carbs from the left hand side - thats the way I do it..be very careful of the carb to head rubbers if they are a bit hard - heat them up with a hair dryer before attempting to twist them around - you will also need to loosen the band clamps on both sides of the carb inlets from the airbox....



have you checked your plug lead, and also the plug cap for integrity - it could be sparking/shorting out internally on the valve cover. if you want to swap the plug leads over from each coil... see if the problem moves to the left cylinder - will soon tell if it is electerical or petrol related...
 

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just a quick question - have you done the valve gaps yet ??

adjusted the camchain also....



maybe even a bad plug might hold the clue



how old is the air filter ??



check your electrical connection to the coil/s - no corrosion build up?
 

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Gotta love this forum fast response. I did bench sync using the steel flat ruller and I bought new rubber plug and they were tight fitting. The right carb is getting plenty of fuel. I ran a little seafoam through the carb and when revving it up I had flames shoot out the exhaust. Is there anything else it could be other than the jets? engine wise or is it carbs for sure. Taking the carbs off is not one of the most enjoyable jobs. Now if anyone can give me a trick for easy on and offs that would be great.


Did you check the air cut off valves for holes? (hold them up to a bright light to see if there are pinholes in them)



There is a post somewhere on removing the carbs,,I don't know if there is a link to it in the Quick Reference thread,,there may be. It is not that hard once you have done it a few times.



I would check the air cut offs and make sure the idle jet is cleaned well,,also make sure all the orings and washers are installed on the idle mixture screws.
 

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Discussion Starter · #8 ·
just a quick question - have you done the valve gaps yet ??

adjusted the camchain also....



maybe even a bad plug might hold the clue



how old is the air filter ??



check your electrical connection to the coil/s - no corrosion build up?


Going out to try switching the coils plugs. Replaced the plugs and correct gap, have not done a valve gap or camchain. Air filter is new. Will update you in a bit. Thanks
 

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Discussion Starter · #9 ·
Alright, guessing that you cant unplug the the wire from the coil and trying to have it reach the other side not going to work, but when I kink the wire near the coil it creates a misfire and when I pulled the left plug and twisted the right side wire just right it has the power on the right side. So 81 custom you might be on to something. So off to fleabay I go. Will keep you updated. I am sure I will be back when it comes to the cam chain and valve gaps. Thanks so much, have heard many say that these motors are bullet proof so not going to give up on it.
 

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run a resistance check on your coils if you have a multimeter - not sure of the values - but probably something on this site how to do it - or consult a manual for your bike. will probably tell if it is the leads or the actual coils - leads can be replaced quite easily - dpending on where the problem may be..



good job
 

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Did you put them through an ultrasonic cleaner? If you did, who long did you leave them in there.



If you only replaced the jets you didn't even do half a job. Jets rarely need to be replaced ... they just need cleaning and the passageways inside the carb need to be cleaned.



There are a bunch of little passageways that need to be cleaned or what you are describing will happen.



By one of Larry's books and you will know what you didn't do that you should have.
 

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Alright, guessing that you cant unplug the the wire from the coil and trying to have it reach the other side not going to work
To switch coils you need to move the whole coil and lead to the other side. you also have to unplug the wire that comes from the cdi and plugs into the coil and switch it too. The yellow wire is always plugged into the coil on the left side and the pink wire always goes to the coil on the right side.









I thought when I listened to the video that when you took the left wire off I could hear the spark arcing to the valve cover and when you removed the wire from the right side I could not hear it arcing,,I figured maybe it was just the way it was recorded.



81 custom wrote;

"leads can be replaced quite easily - dpending on where the problem may be.."



81custom, how do you replace the leads?
 

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Alan,



I'm assuming the leads are not removable from the coil itself, and they are also copper core wire leads. If so you can use a dremel tool to get back to a good connection, and resolder a newer length of lead in... I have not done this myself - but have seen a few who have done this on CB750's - will see if I can find a link for you. If I'm mistaken, I apologise in advance.



http://www.xs11.com/forum/showthread.php?threadid=137



http://forums.sohc4.net/index.php?topic=17310.0



there are two related threads on other forums - might help
 

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Sounds like you might be jumping all over looking for the issue here. My advice is verify one area at a time. I would make sure your getting good spark from both sides first. I would lay money that you still have the original resisters in the plug caps (which will drive you nuts if they go bad). On mine, the plug caps just "unscrew" from the plug wire, then check the resistance. Better yet, replace the resister with a piece of cooper rod to just eliminate it. Check the quick ref section for how to check it out.



After you "KNOW" you are getting a good spark on "both" wires, and if you still have problems, go back through the carbs. Just follow Larry's guide.
 

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Alan,



I'm assuming the leads are not removable from the coil itself, and they are also copper core wire leads. If so you can use a dremel tool to get back to a good connection, and resolder a newer length of lead in... I have not done this myself - but have seen a few who have done this on CB750's - will see if I can find a link for you. If I'm mistaken, I apologise in advance.



http://www.xs11.com/forum/showthread.php?threadid=137



http://forums.sohc4.net/index.php?topic=17310.0



there are two related threads on other forums - might help
Thanks for the links, I did not read them all the way through yet but it looks like it may work.
 
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