Topic: O-ring placement on 78 cb550k carb

[Sugar Pig]

I am rebuilding my carbs, they bike was not running when I got it and am stumped as to the placement of some of the O-rings.

The HONDA kit came with 2 fat ones for the crossover, 1 small, 1 medium, and 1 slightly larger.

According the the drawing on fische the small appears to go on the mixture screw, but does it go above or below the spring.

The medium seems to fit perfectly on the bowl drain screw.

So, that leaves the large.  

Is there nothing for the emulsion tube?

I really tried to search on line and in the manuals but couldn't find the answer.

Thanks

[Kong]

That very little one, the O-ring for the mixture screw, the order it goes on is this:  Going in the direction of moving into the hole in the carb body the order is O-ring, then metal washer, then spring.  So, in order to assemble the stack you would take the bare screw and first put the spring on it, then the metal washer, then last the O-ring.  The purpose of the metal washer is to protect the O-ring from the end of the spring and to act as a thrust washer.

[Sugar Pig]

Thanks for that, I thought I could see something else on the drawing. I was very careful taking these apart and there was no little metal washer on them. I'll check the hardware store and see if I can find a replacement.

So, is my middle size placement correct?

And what about the largest O-ring?

Nothing for the emulsion tube?

[Kong]

You will not find a replacement in the hardware store.  Go take a very very good hard look into the holes on your carbs and take a long sewing needle or a length of small but stiff wire and probe around a bit - don't scratch anything, but dig a little bit.  You may very well find that the original is still down hole and wedged in there by a sliver of what remains of the original O-ring.

[TwoTired]

And what about the largest O-ring?

The very largest oring would be the bowl seal.

Nothing for the emulsion tube?

No.  I've never seen one there.  And, don't see a place for it there.

Did your kit also apply to the CB650's PD Carbs?  They had accelerator pumps that required more o rings than the 550, and those carbs were otherwise similar.
One kit fits all syndrome?

Cheers,

[Sugar Pig]

  The large one is slightly larger than the middle one. My bowl gasket is shaped and wouldn't be mistaken for an O-ring

You're thinking what I am thinking and that is the kit is for several different models and maybe the largest one is just left over.