Topic: What carburetor is this?

[ilikepinkcrayons]

What carbs do I have on my 1975 CB550 (K, i believe)? The punch marks on the right hand side say "62 A 1" (there might be a letter between the 2 and the A, but I don't think so).

Backstory: I bought the bike from the original owner. He tried to rebuild the original carbs at some point, but they didn't work, so he replaced the whole set with these. He gave me the originals with the bike, which clearly show a 022A in the same spot as the "62 A 1".

They are painted with a textured black paint on the carb bodies, the float bowls are greyish silver paint, and the top cover is kinda like hammerite. With exception to the float bowls, the paint is very nice and look like a factory or professional job. Furthermore, the PO did not strike me as the kinda guy to paint the carbs himself, as everything is stock except the handlebars and exhaust.

As I recall, he said the original 4-1 exhaust rusted out, so he replaced it with 4-2. Between the 4-1 and the 022A, I believe the bike is a CB550K.

[jonda500]

He probably bought those carbs from ebay seller carburetorkeith - I have a set from him on my 550F, they don't have the correct number stamp but I have all the correct 069A brass bits inside so they work good for my 550F with stock air filter setup.
John

[ilikepinkcrayons]

Yep, that looks like it.

Besides the jetting, what are the differences between them all? Can I still use the same rebuild kits as for an 022A?  Is there anything I should know about these 62A1 carbs before I continue troubleshooting? I'm running pretty rich with poor fuel economy (22mpg). Just got through a detailed "stage 0" tune-up, so hopefully that helps.

[flybox1]

Leave your jets as they are, and complete an idle plug chop, first.
Your plugs (after IMS adjustments) will tell you if you need to change jetting.

I wouldnt be satisfied until I was near 40mpg.

[ilikepinkcrayons]

Then the carbs are all the same otherwise? I just want to make sure I'm not missing something completely, like the 62A1 is the wrong carb for the bike, or I should be using smaller than normal jets with that carb, etc etc.

[TwoTired]

I've never heard of 62A1 carbs for a Cb550. Are you looking in the right place?  (Each carb mount flange, top right side as you sit on the bike?)  Verify the correct numbers on yours.

A 75 US model should have 022A carbs for a K and 069a carbs for an F model.
Only the F had truly original 4 into 1 with quite curvy down pipes.  Ks were 4 to 4 exhaust.

Whatever exhaust you have now would likely be best served with 022A components inside, provided they are made to Keihin specs.: Jets and needles and settings.  It matters if you have stock airbox/filter.

I think there are some minor casting differences between the 069A and 022A in the area of the pilot needle seat angles.  Should use the solid tipped needles on 069A castings.  Hollow tipped needles on the 022A.

Cheers,

[ilikepinkcrayons]

Strange. I'm definitely looking in the right place for the ID. I tried to take a picture, but it just isn't readable in the image.

The 4-1 exhaust was just a fuzzy memory, but I have the original carb, and it's definitely a 022A. I'll just keep chugging along as is. Hopefully I won't have to get crazy in there.

[Stev-o]

The 4-1 exhaust was just a fuzzy memory, but I have the original carb, and it's definitely a 022A.

On these 40 year old bikes, how do you really know what is original?

[ilikepinkcrayons]

On these 40 year old bikes, how do you really know what is original?

Too true. Thankfully, this PO gave me a very good vibe, and I trust him. He hasn't let me down yet.