Topic: 550 F carbs

[PGF550F]

So I have been lurking on here since picking up a 77 CB 550 F. It is in "decent" condition, most of the parts are on it. It is missing the tach cable and the electrical has clearly been toyed with. I will be doing lots of learning on this bike, it is my first project. I hope I havent bitten off more than I can chew.

I pulled the carbs off the other day to check their condition. I know that I should have 069A carbs on my bike as factory. When I read the carb flanges, carbs 1&2(from left to right) are stamped 069A. Carbs 3&4 are stamped 627B. I have read that the 627B carbs were intended for the 500's, not my 550.

How do I tell if the internals have been changed out in the 627B's to match the 069A's? Or vice versa. From the outside I cannot see any difference between the carbs.
Would Honda have done this to use up barb bodies that were already stamped and just swapped the internals or is it more likely that the PO replaced them for some unknown reason?

I have stock 4into1 exhaust, stock airbox but am missing the filter element completely and will have replace it with something before I can do much.The bike is not running at present, I do not know when it was running last either. Here is a picture from the intake side of my carbs, 1-4 from left to right.


Any thoughts about what to do? should I just confirm what the internals are and replace the o rings and see what I end up with?

[TwoTired]

I can't imagine the carbs left the factory with different markings.  So, a transplant was done to it later, imo.

You can find basic internal setting differences in the Carb FAQ.

If you are using the stock exhaust system and filter box arrangement, I think I would verify that all the carbs have the same internal parts for an 069a set up
Main jet #98
Pilot jet #38
Silde needle numbers matching and the clip on the 2nd groove from top.

The pilot air screw should be solid tipped, rather than hollow.
Then compare the emulsion tubes among the carbs you have for bleed hole size, number, and placement along the tube length.

In my F models, I use a UNI NU-4055 replacement foam air filter.  Get the filter recharge kit for it as well.  It is more economical in the long run.

The carb bodies are the same for 627b and 069A.  I haven't found any difference besides internal parts and settings.

Your picture does show that the choke plates have not been adjusted properly for full open/close position equality.  It will make riding during warm up and partial choke operation problematic.

Cheers,

[PGF550F]

Wow, I have these carbs in front of me and the choke plates look fine to me. I grew up in the age of Fuel Injection, I guess I have lots to learn!!

Thanks for the help Two Tired!! I will likely be looking for more wise words as I tear this bike down to get it running.

[TwoTired]

Wow, I have these carbs in front of me and the choke plates look fine to me.

# 1 doesn't have a plate position adjustment.  But, all the rest do.  Adjust #2 first for position travel both closed and wide open. The do #3, then #4.

It looks like someone ham handed #2's (and t#3's) adjuster and bent it rather than tweak it with a screwdriver.

It's just a detail that makes the machine better to operate during starting and warm up.

However, it could also be some photography trick that makes them look misaligned.  If they look fine to you on close inspection.  Then just ignore me.

Cheers,

[PGF550F]

Yes, 2 and T3 adjusters look bent to me, as compared to the last one. I wasnt sure if thats how they should look.I guess I am not immune to the workings of a PO either. With a 30 yar old bike you never know what has been done to it sometimes. I just checked the air bleed screws on 3 + 4 carbs this morning. They are solid tipped and set at 1 1/8-1/2 turns.