Topic: Quick help with carb emulsifier tube

[Tews19]

Swapped out my main jets and my emulsifier tube came out with it. Now I'm confused as the direction to put the emulsifier tube back in. Does the wider opening sit right above the main jet or the opposite way with the smaller holes more to the top

[harisuluv]

At first I was thinking of 77-78 carbs and thinking what the heck you were talking about!

For the non PD style earlier carbs, the part with the little hole goes in the tube.  The end with the bigger opening is the side that the leaf spring attaches to.  Hope that helps.

[dave500]

the smaller end goes up,the bottom is sort of flush and the top has a stepped down look to it,the leaf spring connects to the actual jet,,that tube dissapears into the body.,the way your holding it is the correct way up.,,,,howd you get them callouses?

[harisuluv]

Ok, that was not what you were talking about lol sorry.

[Tews19]

Ah #$%*
I had a panic attack and lost all common sense. Vintage races are tomorrow and when I was swapping out the mains the whole booger fell out. Sorry guys for an obvious easy question I know I could have not posted if I had a calm state of mind.

All fixed now. I guess I should ask, why the hell would she come out so easy? I did clean them out last week, the carbs that is.

[new2bikes-again]

Can anyone tell me if my 1974 CB550 would have a similar tube? I've read suggestions on here about being sure to clean those out (you may think you cleaned them..Did you check the emulsifier tubes?!) This is the first pic I've seen. And...no I didn't clean nor check them!

[dave500]

if your 550 has the "type one"carbs they are the same,,if yours is later and has the "pd" type carb the main jet screws into the tube,also clean the pilot or slow jet/idle jet,it has a similar emulsifying feature,those holes are tiny,i slightly chamfer the tubes holes.

[tomkimberly]

Can anyone tell me if my 1974 CB550 would have a similar tube? I've read suggestions on here about being sure to clean those out (you may think you cleaned them..Did you check the emulsifier tubes?!) This is the first pic I've seen. And...no I didn't clean nor check them!

Take them out and clean them, it makes a world of difference in how these bikes run.

Tom

[Deltarider]

why the hell would she come out so easy?

Be glad they did! Others find it difficult to pry them loose (preferably with a wooden toothpic or similar).

Can anyone tell me if my 1974 CB550 would have a similar tube?

Yes.

And...no I didn't clean nor check them!

You should.
Dave, may I ask what carbs you've found that needle jet (right in ypur pic) in? It has an extra little hole, doesn't it?
My dictionary doesn't know what callouses are. Or is the word calluses?

[dave500]

a callous is a hard skin lump that occurs on your flesh from doing work,like a workman has heavily calloused hands,,it could also be caused from something else?thats a genuine needle jet tube,early 500 i think,,the three holes are larger on the lower then the next two get smaller towards the top and has one about halfway,these are the good ones.

[Deltarider]

thats a genuine needle jet tube,early 500 i think,,the three holes are larger on the lower then the next two get smaller towards the top and has one about halfway,these are the good ones.

Isn't this interesting! For years I've been trying to solve the enigma of the difference in jetting between CB500s in (some) European countries and the rest of the world. Some of you might remember my first post in this forum.
http://forums.sohc4.net/index.php?topic=17322.msg179042#msg179042. The question then was: how could an European CB500 with #78 main jets perform equally good as the ones with #100 main jets? Already then I wrote "Maybe Honda did something clever with the needles" and now after years the puzzle is coming together. BTW, my genuine tubes have 5 little holes on each side and they're all equal as shown in:
http://shop.honda4.nl/catalog/product_info.php?products_id=1322 (Click to enlarge)
Strange is partnumber is the same for all CB500, 500K1-2 needle sets. Maybe other CB500 owners like to describe their emulsion tubes.

[SohRon]

a callous is a hard skin lump that occurs on your flesh

"Callous" is a hard ATTITUDE, not a skin condition. For that, you'd have to have calluses.

My question re: emulsion tubes is that I've heard that you should: open up all of the holes; only half of the holes; or add extra holes in between the holes already there (leaning out the mixture). Just what is the best procedure with these things?

[dave500]

those keyster replacements come with five holes the same size,probably because its easier to do than swap tooling for smaller holes?some like to drill them out,i never have,i just chamfer the holes slightly,that gives you twice the power and half the fuel consumption.

[Deltarider]

just chamfer the holes slightly

How did you do that?
Another question. I remember I've seen a view of that needle jet in your picture, the one with that extra crosshole, somewhere. Now, I have quite an archive of the 500 and 550s, but sofar I have not been able to trace it. Does anyone know? It wasn't a photograph, but a view. I remember on seeing that I asked myself: hey, what's that extra little hole doing there?

[Tews19]

just chamfer the holes slightly

How did you do that?
Another question. I remember I've seen a view of that needle jet in your picture, the one with that extra crosshole, somewhere. Now, I have quite an archive of the 500 and 550s, but sofar I have not been able to trace it. Does anyone know? It wasn't a photograph, but a view. I remember on seeing that I asked myself: hey, what's that extra little hole doing there?

Mine are the same as Dave shows in this pick on the right. I too have the one hole in the side all by it self. I was also thinking why not make all holes the same size?

[Stev-o]

Tews - is it back together and running good?

[Deltarider]

Mine are the same as Dave shows in this pick on the right. I too have the one hole in the side all by it self.

But... is yours a 500 or a 550?

[Tews19]

Stev-o it was back together about 5 min after making the thread. She ran well yesterday to Road America and when I was on the track beating her up. My new sprockets will be in on Tuesday so until then she is in the garage. I receive my carb sync and tool in the mail Friday and Saturday. Some more tweaking to come. Of course I will try to sync the 750 first. I really want to put miles on that ride. I will be getting ride of the tank on the 550 soon. Picking up a new one tomorrow! The fun never ends with the bikes.


Delta I have a 550F. 1975. Run 069A carbs.  Current setting is 4 notch, 105 mains, 38 slows....

[TwoTired]

Delta's bike has a restrictor at the duct entrance to increase all the pressure differentials between that restrictor and the intake valve.
All the pressure differentials inside the carb throats are more extreme relative to outside atmospheric than the much large air inlet of the US models.

ALL the carb jets will provide more fuel with deeper pressure differentials applied to them.  That is why the 649a carb require #78 mains whereas the US models use #100 or (#98 for the 550F).  At higher RPMs (WOT) the restrictor deepens the carb throat pressure all through the duct to that inlet restrictor, which delays outside atmospheric pressure from entering the duct.

It is elementary duct physics.
http://forums.sohc4.net/index.php?topic=83904.msg945765#msg945765

[Deltarider]

Dave, are you sure yours didn't come from some 550?

[dave500]

pretty sure?ive had mix matched pre tampered carbs so anything is possible really.







,i just spin a slightly larger drill bit between thumb and forefinger to make that chamfer.