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Discussion Starter · #1 ·
Aired up the tires, found the reason for the oil light always on (thanks, forum, just a blown bulb), and tried to ride the '79 CX500 a little.

It wasn't pretty.



I know I had to pay two years of back taxes so I assume it's sat up and will need the carbs gone through.

Because...It sounds like it's only firing on the right side and it will hardly take the throttle. Lots of popping on decel with the awful straight pipes on there. Gonna fix that soon, thanks to Randall's exhaust parts.



But the other thing: At 4500 RPMs, it JUMPS to life. It goes instantly from popping, lugging, won't-take-the-gas, to VROOM, snapping my neck back as it leaps forward and both cylinders get fuel and spark. So...is this indicative of the low speed coils out?
 

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So...is this indicative of the low speed coils out?



Nope! "Low speed coils out" would make it refuse to start at all.



My guess would be fuel / air problems only. Check the airbox + filter + intake manifolds. Clean the carbs and sync them. That ought to be it, pretty much!



One of my CX-es did like yours, when I bought it. Easily fixed.



Sture
 

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Lots of popping on decel with the awful straight pipes on there. Gonna fix that soon, thanks to Randall's exhaust parts.
I forgot to tell you, your parts went out yesterday. They passed through Des Moines early this afternoon. I'll PM you the tracking number.





At 4500 RPMs, it JUMPS to life. It goes instantly from popping, lugging, won't-take-the-gas, to VROOM, snapping my neck back as it leaps forward and both cylinders get fuel and spark.
That's where the other cylinder is kicking in. Most likely a clogged idle passage in the cold carb.





R
 

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Discussion Starter · #4 ·
WOOT!!! Thanks, THAT I can handle! I may not know these carbs yet, but carb cleaning doesn't scare me at all.



Airbox is intact and filter is clean, checked all that before making an offer. It's a paper filter, so no oil on it, right? There's dried fuel mess all over the bowls, I know I need bowl gaskets. I'll wait to order them till I see what kind of mess is in there, might need a whole rebuild kit.



I have a Haynes. It is very hard to use. I'm hoping to bid on a Honda Shop Manual on the 'bay soon....



My ears are wide open for any tips you have....
 

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WOOT!!! Thanks, THAT I can handle! I may not know these carbs yet, but carb cleaning doesn't scare me at all.



Airbox is intact and filter is clean, checked all that before making an offer. It's a paper filter, so no oil on it, right? There's dried fuel mess all over the bowls, I know I need bowl gaskets. I'll wait to order them till I see what kind of mess is in there, might need a whole rebuild kit.



I have a Haynes. It is very hard to use. I'm hoping to bid on a Honda Shop Manual on the 'bay soon....



My ears are wide open for any tips you have....
i agree with Randall,that idle curcuit is blocked or partly blocked.for your first risk free carb clean follow sheps link

http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=19&t=140
 

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Forget eBay. Just download it.



Be sure to check the addenda in chapters 21 & 22 for info particular to your '79 Custom.





R
CB,BUY a hardback,it will pay dividends


Randall,i bet you have one to take bed with you
 

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Randall,i bet you have one to take bed with you
I printed it and put it in a 3-ring binder. It lives in the garage with the rest of my tools.





R
 

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CB,BUY a hardback,it will pay dividends
I had assumed it was on CD.



Jenn, if you do buy a hard copy, don't get this one. I think $125 +shipping for an FSM is just a little obscene, even for NOS.



There are a couple currently in the $10 range. If you'd have to pay to print it, one of those would be worthwhile.





R
 

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I have had plugged idle circuits before,,the bike was usually drivable once it was above a couple thousand rpm and never had any popping on decel caused by one,,you may have a couple of things going on although the popping may be from having straight pipes.

While you are cleaning the carbs check your air cut-off valves,,they are on the sides of the carbs under the little covers held on by two screws. To check them once you have them apart, hold the diaphragms up to a bright light to check for pin holes. If you do find holes or tears in them you can get replacements or block them off with no negative results.
 

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Discussion Starter · #11 ·
ooh, good stuff. Thanks.



Got one bowl off yesterday, just to see if the jets were all boogered up. Looks good so far, a little dark varnish but no damaged parts.
 

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Discussion Starter · #12 ·
I'm not sure how the '79 carbs differ from other years. Any glaring/obvious differences?
 

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Your carbs are much like all the CX carbs,,I think that yours probably don't have the accelerator pump which is the major difference between the earlier and later style CX carbs.



This picture by Larry shows the idle circuit, when you are cleaning the carbs make sure that all the passages shown are clear,,either by blowing air or spraying cleaner through the holes/jets and checking to see if if comes out the corresponding holes.







Also see these links for some tips,



Carb Cut-away pics.



Carb Cleaning.
 

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Discussion Starter · #14 ·
Even better. Thanks. I hate to ask the same questions over and over but the search option just yields too many results sometimes. I appreciate these links, I don't know they exist usually until somebody posts them.



So no accelerator pump, good....the diaphragms on the side, whatever they are, they're not in great shape. I see they are not too expensive from TAS motorsports.

I need float needles, bowl gaskets and fuel rail o-rings, all available at TAS, unless ya'll say there's a better spot.



So this sucks that I'm going to have to break the carbs off the rack, but there's so far no damage from anybody else messing around in there.



And, just eyeballing it, these ain't nowhere near synched. No wonder the left side wasn't running, the pilot hole was all the way covered.



I'm about to put the carbs in Pine Sol for a couple days while parts show up. Learned the trick from my Nighthawk forum.

http://nighthawk-forums.com/index.php/topic,4472.0/highlight,pine+sol+degreaser.html

Precious few part, thank goodness. I may have a good-running bike for well under a grand, when it's all said and done....
 

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Discussion Starter · #16 ·
Cool, TAS sold me just the parts I need instead of the whole kit, and I got a much better price that way. They have my steering bearings too.

I've wondered if I would get good use from an ultrasonic cleaner. Never wanted to drop the dough....



I'm waiting to do bearings--I got off the top triple today and the adjuster nut under it was finger loose
.

I think the "wandering in the road" feeling won't be there on the next ride.
 
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