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Discussion Starter · #1 ·
Hey,

I have a 1980 cx500, recently rebuilt the carbies with new jets, pilot screw, o-rings, ect...
It had some scoring on the top section, I think due to I had a rust issue with my tank.
I have just done a compression test on both cylinders and both are at 100psi.
When I start it up it only runs on the right cylinder.
The right carbies has a bunch of vacuum going through it as when I cover the carbie inlet it dies.
The left has no vacuum going through it,
What could this be?
 

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Premium Member
1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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12,658 Posts
Missing o-ring at the intake port?
Welcome, by the way!
 

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Premium Member
1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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12,658 Posts
Yes. If there's a large leak there, it might not draw through the carb.
 

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Super Moderator
'84 CX650E that is evolving into a GL500
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19,260 Posts
Did you separate the carbs or disturb the linkages between them in any way when you had them apart?If so I'd start by checking them for assembly errors (particularly at the balance adjuster).
Did you check that both throttle butterflies were moving together and starting to open at close to the same time when you put them back together?
How about the chokes?

Where did you get the jets, screws &c that you replaced? The original ones almost never need to be replaced and the ones in aftermarket carb kits are often so far out of spec that they can have adverse effects on tuning the carbs. They probably aren't causing your current problem but if you have them apart to fix this it might not be a bad idea to either put the original parts back or get replacements from a Honda dealer.

Welcome to the forum. Please add your location and your bike's model and model year (NOT year first registered as UK paperwork shows) to your profile so that you don't have to remember to tell us every time and we don't have to keep asking when you forget (see Forum Settings link in my signature).

And welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike is about 4 decades old and may or may not have had all of the maintenance necessary to keep it safe & reliable so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage.
I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel (old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet). If your bike still has the original rubber brake line(s) (should be replaced every 2 or 3 fluid changes = 5 or 6 years) I recommend shopping for modern stainless braided ones (they last practically forever and double the life of the fluid). And don't forget things like the rad hoses and the boot between the engine and swingarm (they can crack on the bottom where you don't see it).
 

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Discussion Starter · #7 ·
Yes I did separate the two but I was very careful to video and take photos of everything so it was put back together correctly, also the throttle butterflies are moving together, the choke also it connected and move together.

I have rejetted it for a more flowing exhaust and pod filter for the intake.

I will try and figure out how to put a signature in.

And yes I plan on upgrading break lines to steel braided, I also have a 1982 cx500 sport that I'm going to do the same to.
 

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Super Moderator
'84 CX650E that is evolving into a GL500
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As I said, the Forum Settings link in my signature takes you to instructions for adding the information to your profile so that it will show up whenever you post (note my bike's model & year below my name and if you mouse over my name or avatar pic you will see my location and forum stats.

It is pretty common for people to get the washers &/or spring of the balance adjustment in the wrong order, but if your throttle butterflies are opening at close to the same time and the chokes are both open the only other thing I can think of that would block airflow through one carb is a stuck slide. Tell us more about what you mean by "It had some scoring on the top section"
 
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