As far as the 'oldstyle' carbs like yours, the 069A carbs were on the 'F' models, the 'K' models had either 022A or 087A. It had only to do with 4-1 vs 4-4 exhausts. What intrigues me, is that your frame says it is a K and - correct me if I'm wrong - 1977 ment K3, which model had totally different PD carbs and also a different manifold. So... if the oldstyle carbs on your bike fit nicely to the manifold, it means at least that manifold is from a model that had the oldstyle carbs and maybe the whole engine is. BTW these engines are technically all the same. If you want to be sure, you can check your engine- and framenumbers with those listed in the first four pages of the CB550 Parts Lists. They're all here:
http://www.honda4fun.com/materiale-documentazione-tecnica/parts-list/parts-list-cb550.
Some years ago I've composed an overview of the oldstyle carbs. It's attached below.
Back to the leaking. Here the standard the procedure.
When carbs have been left drained for a long time like hibernation, sometimes it will be enough to give it time and allow the seals to swell again by the fuel.
Carb peeing fuel out of its overflow tube, often indicates its float needle doesn't close the valve. This is often seen when bike has been inactive for a long period of time or carbs have been tampered with. Overflow can be caused by even a small particle of dirt between the float needle's tip and the valve or the float itself is hindered in its movement.
1. Detach all 4 overflow tubes from their brass pipes to identify which carb it is. Do not pull the tube without rolling it between thumb and finger, this to prevent damage.
2. Once identified, tap with the stub end of a screwdiver its floatbowl and hope this will help to get rid of the dirt.
3. If not, close the petcock, unscrew the drain plug completely. Now with the drain plug removed, open and close the petcock a few times, to create a flush of fuel that can flush out the dirt between the float needle's tip (that is now down) and the valve.
4. When needed, combine step 2 and 3.
In most cases this does it. Ofcourse you will collect all the fuel - inspect it for dirt or excessive rust - and pour it in your tank again.
5. When the above steps don't help, it is necessary to remove the floatbowl for further inspection.
Also possible is that PO has fitted too wide fuel lines. Some members have reported a cracked brass overflow pipe.
If the O-rings on the T-joints do not leak, I'd leave them alone. Mine are 45 years old and still don't leak (Honda fitted two on each side). Do not be tempted to replace the original brassware, that is: not unless you are 100% sure you need to!
