500 carbs what does what question.

[Nurse Julie]

Yes Ted. The carb bodies are the same, it's the jetting etc that is different.

[DomP]

Sorry to butt in on this Ted but how critical is the airbox lid to the running of a 550?  I don't have a lid yet due to my custom seat design so I'm currently trying to tune it without.  My plan is to mould one with a similar sized mesh aperture.

[McCabe-Thiele (Ted)]

I have no practical or anecdotal evidence about what effect if any having the lid makes.
On the carb induction side the air filter will give a certain restriction to the air flow into the carbs so there will be a pressure loss across the air filter itself. Although the lid covers the top of the air box the top section with the gauze fitted is not going to be the main cause of additional intake restriction. If there is a consequence it might run marginally leaner at higher rpm.

[Bryanj]

Dom, sorry cant remember which 550 you have, the us K0,1,2 use the 500 cover the European F and K3 use a different one that restricts air flow more hence smaller jets

[DomP]

Dom, sorry cant remember which 550 you have, the us K0,1,2 use the 500 cover the European F and K3 use a different one that restricts air flow more hence smaller jets

F1 Bryan, in the absence of a filter cover and my seat design means I need make one in fibreglass I think, so having no cover is definitely going to cause me set up problems then?

I have discovered a big oversight on my part while assembling my carbs, I had used two open pipes where there should have been link pipe between no2 and no3 carb so they were drawing in air.

[McCabe-Thiele (Ted)]

Aside from fuel connections the only other links between carbs 1&2 then 3&4  that  I can think of are vent pipes ??

They are unlikely to be able to draw air into the system as they vent to atmosphere anyway to allow fresh fuel into the carb bowls iirc.

Update:-  Aside from the obvious flexible connectors over tightening the manifold to cylinder head nuts can mean the O rings will not seal due to bending of the alloy faces or the wrong sized O rings.

[DomP]

You're right Ted, I initially looked at a YouTube video and they were looped together, remembering that is how mine were when I got my 550 I did the same this evening.   But now I see what you are saying about them being vents for the bowls so I'll return them to how I first had them.  In trying to solve some issues I'm seeing problems that aren't there😆

[McCabe-Thiele (Ted)]

The Emulsion tubes that I removed from my carbs had 5 holes on one side & one on the opposite side.
The two top holes are slightly smaller than the others.
I suspect the Emulsion tubes are replacements fitted by Gerben as they virtually fell out when I removed the main jets.

How many holes were there on the geuine Keihin part for a 500 has anyone here counted them?

[deltarider]

The Emulsion tubes that I removed from my carbs had 5 holes on one side & one on the opposite side.
The two top holes are slightly smaller than the others.
I suspect the Emulsion tubes are replacements fitted by Gerben as they virtually fell out when I removed the main jets.

Gerben just did the right thing to the 069A carbs in front of him. Falling out is not a sign they were not right. Mine also fall out, which makes servicing much easier btw.

How many holes were there on the geuine Keihin part for a 500 has anyone here counted them?

Five on each side and they are all the same size. Very early CB500s may have had different tubes (the source is weak), but I've never encountered them.

[McCabe-Thiele (Ted)]

So I have been sold the wrong tubes for my 500 by DS as they were the same - looks as if Gerben use the same supplier.

[deltarider]

So I have been sold the wrong tubes for my 500 by DS as they were the same - looks as if Gerben use the same supplier.

The correct path for ordering is:
1. Establish what exact model bike you have, by comparing the frame- and enginenumbers of yours to those listed in the first few pages of the CB500/550 partslists. Pay attention to the carb identification number in the same page and verify yours has the original rack or not.
2. Find the correct Honda partnumber in the apropiate partslist.  They're all here: https://www.honda4fun.com/materiale/documentazione-tecnica
In addition, you may want to consult the overview I've composed.
3. Suppliers of aftermarket parts should clearly indicate which of their parts match which models. 

[Bryanj]

Forget all of that Delta this is NOT an original bike but built from a garage full of bits as Ted knew when he bought it so non of the comparisons will work

[deltarider]

Provided you can read either 498- or 544cc on the barrel and the number stamped in the carbs you will at least have some sort  of a starting point. Slow as well as main jets have their size indicated and even the jet needles have a stamped in number.
Six months ago I have contacted Gerben to ask him if he had seen any difference in the venturis.
As far as I know, the numbers on the bodies only refer to the internal parts such as jets, needles, air screw settings, etc.
As far as I know, the bodies are all identical. I have never been able to detect a difference there.
[...]

[McCabe-Thiele (Ted)]

My block is stamped 498 cc my Pilot Jets & Main Jets are stamped 40/100 I have solid Brass air screws not the drilled type.

Ive looked at the 500 K1 UK parts book in the link you have provided but can't see a part number for the seperate Emulsion Tube only on the USA model. No one seems to give details of the layout & number of holes in the tube.

I am quite disappointed that DS sells the needle & tube kit BGABC-323-004P as described below for a CB500 K1.

"A direct replacement needle jet, produced by the most highly respected carburettor component manufacturer in Japan, assuring you of the highest quality part which was is no longer available from Honda".

I'm only guessing it's Keyster as they appear to be a Japanese manufacturer.

[deltarider]

The solid air screws are typical for the 069A carbs (see pics). Apart from the very, very early CB500s where the parts concerned had separate partnumbers*, the CB500 NEEDLE SET, JET comes as a set: needle, clip and tube. To be honest, I have no idea how critical the differences are, as far as brassware. Personally I have no experience with aftermarket brassware.
* according to that Japanese JDM Partslist. https://www.dropbox.com/scl/fi/v37q90p9ptk45u60ml5tr/CB500K0%20JDM%20Manual.pdf?rlkey=hukkwrheiwtw5ri7v2p77c5dc&e=1&dl=0