Honda CX 500 Forum banner

How can I richen the slow speed circuit?

1300 Views 4 Replies 4 Participants Last post by  DanCX500
Hi. I live in California, so we can blame my fuel mixture problem on that! When I tour every year outside of CA, I have a new bike!And when I return home, I wonder why I still live here. It has gotten to the point where we should just call our gasoline "ethanol fortified with gas!" Bottom line is I must richen up the idle/slow circuit on my 1980 CX500 carbs. The carbs have been disassembled and cleaned several times. They are spotless. The main needles are shimmed up to richen the mid-upper range. The limiter caps on the idle mixture screws are bypassed, and turning the screws out until nearly falling out still gives me a very lean slow circuit. The air cutoff diaphragms are intact, with no holes. The intake manifolds have brand new O-rings. My 1984 Nighthawk's carbs have been cleaned a few times, but gradually started running so poorly on our gas that I went up two sizes on the slow speed jets. Just picked them up today. That got me thinking of doing that to my CX500, but the carb appears as if the slow speed jet is pressed into the carb, never to be removed. Is this correct? How else can I richen up the slow circuit if I cannot unscrew the slow jets? I have a pair of 1978 carbs (no accelerator pump) and I am so deperate I may try cleaning those up and trying them in hopes that the 1978 carbs might be jetted richer in the slow speed circuit. But I have no idea. The only other thought I have is if air could be leaking past the plastic bushings/washers on the throttle butterfly shaft. It is the only non-metal item which cannot be removed prior to carb cleaner dunking, and I always wondered how well they hold up to dunking in Berryman carb dip. Can air leak past the butterfly shaft if these are cracked out of sight? Any other suggestions on how to richen the slow speed circuit? Anybody with thoughts, I would appreciate also forwarding to my email, as I only have internet access once a week. Thanks.
See less See more
1 - 5 of 5 Posts
There are quite a few members of this forum from California, I have not heard any of them mention needing to enrich the idle mixture beyond what they can adjust with the mixture screws.

If you are having a problem, maybe the idle circuits need to be cleaned. Have a look at some of the carb cleaning threads.
If you are near Sacramento, search out Larry, he goes by LRCXed. You will be the luckiest guy around, as he is the master when it comes to these carbs....he literally wrote the book. Even if you aren't, there is help here soon.

He completely knows his stuff, and did the full restoration on my G-Loria. The Quick Reference has a ton of help too, so give that a read.

Oh, and take a moment to update your profile with your location, and put your bike year and model in the signature line, that way we can always know what we are talking about.

Welcome aboard.

Joel in the Couve
See less See more
"I would appreciate also forwarding to my email, as I only have internet access once a week."

First off, the above coment I made has to qualify for "Brain Fart of the Month" award! I got home, thought about the absurdity of what I said, and desperately hoped that first impressions aren't lasting impressions!

Thanks for the replies. These carbs have been cleaned, soaked, sprayed, poked and prodded with jet cleaner wires several times, so I can't reasonably imagine it is a gunk issue, especially since the things seem to run fine when I am out of good ol' California. Thanks for the replies. I am 90 minutes from Sacramento. I will pursue the LRCXed lead. Although, a reply to my question would still be appreciated. That is, can the slow speed jet be removed/replaced?
You've probably all ready read the info I'm going to point you to.....

Check out the links in my sig.
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.