Topic: Head identification

[andrewp16@yahoo.com]

Does anyone know how to ID a head and carbs for a '75 550F?
 
I have someone who has a used head available, but I can't see any numbers from the pictures. He isn't sure what model CB bike it's from. There is also a rack of carbs, but also can't see any stampings on them either. mine are on the bike and I can't see much as far as numbers, it looks like there are casting numbers in the middle intake side, but hard to make them out. I also looked through the service manual and nothing listed for the carb model.

[bryanj]

All 500 and 550 heads are the same so you should be able to find pics on ebay.
500 and 550 to 76 are basicacly the same carb castings where the top is shaped like a coffin with a screw on each side, the 77/78 550 had horrible PD carbs which had a P shaped top with a screw top and bottom

[HondaMan]

The early carbs have faintly-stamped numbers on them, on their flanges where they are screwed against the front mounting plate.
The stamping is very faint: I couldn't get a clear picture of the ones I had here for my last book, but their numbers will be:
022, 022A, 087A or 627. If it isn't these numbers, they are from later bikes.

[Deltarider]

Welcome! My first step would be to identify which model is yours. This is done by comparing your frame- and enginenumber to those listed in the first few pages of the various CB550 parts lists. They are al here: https://www.honda4fun.com/materiale/documentazione-tecnica
If you have pinpointed your model - the year is irrelevant -, use that parts list from then on. You may have to look up to see if any part has eventually been modified during the production period of that specific model. You will also find what carbs your model originally had and what differences the bike had for your home country. I have composed an overview of settings for all oldstyle CB500/550 carbs, which you will find attached with a pic showing where the stamped number should be (courtesy Dave500).

[jlh3rd]

Does anyone know how to ID a head and carbs for a '75 550F?
 
I have someone who has a used head available, but I can't see any numbers from the pictures. He isn't sure what model CB bike it's from. There is also a rack of carbs, but also can't see any stampings on them either. mine are on the bike and I can't see much as far as numbers, it looks like there are casting numbers in the middle intake side, but hard to make them out. I also looked through the service manual and nothing listed for the carb model.

this is a pic. of my U.S 1975 550F. A little easier to see, 069A, carb model.

[andrewp16@yahoo.com]

There is some great info here, thanks for getting back to me with it. I'll spend some time and look thru in more detail, wish I could read Italian for some of this!

[andrewp16@yahoo.com]

So I have the carbs identified, they're 22A model which unfortunately is for a K, I need 69A. they need a rebuild but might come in handy for diagnosing my frustrating lazy idle issue. The head I'm still not able to ID, it's not from the same bike as the carbs still have the manifolds attached. There is a 19C cast in the back side, if that helps anyone?

[andrewp16@yahoo.com]

More pictures

[denward17]

My head is 6218 on a '76 550K.  Not sure if that number means anything, but it may.

[andrewp16@yahoo.com]

Where do you find the number? Also wondering if there is a chart somewhere.

[denward17]

On the intake side of head at the back......

6216, not 6218

[bryanj]

I say agian IT DONT MATTER all the heads are the same!

Later rocker covers are supposedly better due to pinned shaft but that was only on 76/77 so it took Honda, who value there reputation, from 71 to 77 to decide it needed modifying!

The carbs you have will run fine with correct jets

[Don R]

 Most often, the casting numbers lead to a mystery. They were more for identifying the mold that they came out of than the year they were machined.
 The carb numbers are mostly for identifying the jetting used in that model, aside from the obvious design changes in the smog motors the castings were the same.

[andrewp16@yahoo.com]

Thanks for the replies, but I'm not sure this is a 550 head thats what I'm trying to confirm. Not sure how to confirm it isn't a 400, 350, or 500? I wouldn't think they would all be the same? I'm just really surprised there isn't a part number somewhere. Since there was an overlap in years between these models, there must have been some way for the factory to know which model head to use.

[bryanj]

YET AGAIN ALL 500 AND 550 ARE THE SAME 400 is different and that pic IS NOT 400

[HondaMan]

The carbs will swap OK. The 069A series were the first 'emissions-controlled' carbs for the 550. Their mainjetting and idle jetting is the same, or within 2% of each other, close enough to make them run.

What IS different in the 069A carbs is the needles in the slides of the carbs. They require the clips be in the 2nd notch (from the blunt end) in the 069 or the 3rd notch in the 069A, but these changes were made to lean out the midrange exhaust mixture to meet late-year emission changes.

They will both work with any head.

[andrewp16@yahoo.com]

Sounds good, thanks for the info.