Topic: 78 cb550 carb help

[gene03079]

Anyone have a good manual on the 78 CB550 carbs?

These beasts are a bit different than most I have worked on. So far I have had them out twice and just cant get the hang of them. I plan on pulling them one more time this week to make sure they are clean. I have the floats set at 14 but I then read 12.5 may be the correct number. The screws on the bottom engine side are set at 1.5 turns out. I have found getting them off and on with the stock airbox gets easier after a few tries.

[TwoTired]

The only manual for these, that I know of, is the Honda Shop manual supplements.  (Chapter 19).

These cover the 77 K3 PD carbs (same general type as yours)

However, for the 78 with the #42 pilot jets, the Honda spec book says 12.5 mm float height for the 78 model.
The Carb FAQ has this information.

Cheers,

[bryanj]

Yup only Manual is the supplement to the original Honda and to be honest it aint that good and it only sez 77 but what it does say is:-

Main jet 90
Air jet 130
Slow jet 38
Slow air jet 150
Jet needle 3rd groove E2349F
Float height 14.5mm

pilot jets normally 1 1/2 turns out

These are for the 550K3, there was a 500K3 in some countries and those numbers are different

[bozo4onion]

Good luck. How many times till removing gets easier? I am converting to stock and was amazed at the difficult installation w/orig. box. And....I was just curious how my mighty 550 would run w/o pods and w/ the stock box. Well hours later I found out it runs much better w/stock system. I think the pods were the only modification I had (no re-jetting). But now I have to remove it again to reset floats and change leaking gaskets etc. Any tips?? BTW I think I have a copy of the Honda carb. manual if you want me to email it to you. Large file. 

[TwoTired]

This is from the Honda Spec booklet...

[gene03079]

Thanks guys. This week end I pull again and recheck them.

I think I will try the level at 12 mm  that may be part of the problem.

[bryanj]

You have the advantage on me TT as the 78 never got to uk so there is no paperwork! There were some sold in 78/79 BUT they were "leftover" 77's

[gene03079]

I pulled the carbs again today. I am getting good at removing them now. During the disassembly I found someone forgot to tighten down the mains during the last cleaning. I re cleaned everything and set the floats to 12.5. This time I also tightened the mains down as they don't work when sitting in the bottom of the bowls. After reassemble I gave it try. Bike started right up and ran fairly smooth. A little more syncing and I think they will be fine.

Thanks for the help guys. You made a hard job easy.