Topic: CB550 Carburetor Replacement ideas

[Deltarider]

Maybe this helps. From 08:30 on in:

[Oddjob]

Not really, I don't speak german that well and a real view of the galleries would maybe help to understand why they block, maybe they narrow at one point for instance. I have quite a few carb bodies BUT none that are scrap or I'd cut one in half myself, the only one I know for sure is Ammans, so I thought I'd see if he was willing to help out.

I've blasted all the galleries in mine and I know where they come out, what I'd like to know for sure is that they are where I think they are, the idle circuit for example comes out in 3 places IIRC, all must be blockage free in order for it to work perfectly.

[Deltarider]

The idle circuit has 4 openings. The one in the carb mouth will never be blocked as long as you use genuine Honda cellulose airfilter elements. Me thinks Marco explains it really well when he indicates the routes with his red straw. BTW, you can opt for English subtitles, alas...  translation is not perfect. The galleries are wider than the jets, so I don't see much of a problem there.
But for me it is easy to speak; my carbs have never been inactive for any longer than say 5 months. Moreover in winter every two months I drain the carbs and then crank the engine so the downgoing pistons can suck the jets dry. Then I let the floatbowls fill themselves again. This takes longer than you may think.  In principle gasoline cleans really well. When carbs have been left for years, it's another story and you may have to opt for ultrasonic, but... it's not a guarantee, three companies specialised in this service, informed me. There is a good video about how to do it the right way, but it's also in German:

Note that there are quite a few things one can do wrong*. Cleaning the outside of the carbs is a relative fruitless indeavour imo. After a ride they will be dusty as before. No problem when the seals are OK. The carbs on mine show a nice contrast: outside dirty, the interior... spotless, sterile.
* And in these two video's Vergaseronkel demonstrates how you can perfectly clean our type carbs (CB350F/CB500 Four) without separating and ultrasonic treatment:

and

[Amann31]

Yeah I would be willing to chop the other carb in half for science and Il post some pictures. Do you think cutting along the fore and aft centerline along the middle of the intake hole would be best?


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[Oddjob]

Probably, as the idle jet outlet is right in the centre of the inlet tract, so it should show where other drillings are intercepting it. That’s the theory anyway.

[Deltarider]

The best demonstration (so far) I have seen is Marco's.
From 14:45 - 16:00 it is about the main, from 16:00 on it is about the 'slow' route.

Good luck in cutting the carbs so precisely that we will be able to see more of the inside. Personally I hold it for impossible. On the other hand... someone has managed to cut a #40 slow jet in exact halves (see pic). Maybe scanning could bring results. In ports they can scan even sea containers for drugs, weapons and what not, so who knows. Question is... who has access to such a scanner?
I do not agree on everything Marco has chosen to do.
a) I never felt the urge to separate the carbs from each other.
b) I would not tap the needle jet into position. I just manually press it in as the main jet will fix it in its position, due to the leaf spring which in its turn will force the main jet upwards.
c) I would not have chosen Keyster parts.
d) Marco sets the airscrews at 1,5 turns out, which - in my experience - is too lean for a CB500 to provide good driveability in acceleration. For our CB500 models one turn ⁺/_- ¹/₈ was advised by Honda. It wouldn't surprise me if Marco, on finetuning, had to turn them in a bit. BTW, I hold the carb setting data concerning the CB500-A in that booklet, edited by American Honda in 1977 for an error (see the concerning note in the overview below).   

[HondaMan]

This sort of a chip off the mainjet holder is tough to repair for the long haul. I have a local welder who can do it, but the cost is like another set of carbs, plus rebuild kits(!). I've only done it once with him, but he is the most amazing welder I've ever met: he went with me through a 4-step reweld-mill-reweld-mill (repeat 4x) on a sandcast 750 engine case set some years ago, and while painful, we managed to save the engine. He always yells at me when i bring him this stuff, but I think he enjoys doing artwork in weld.