I have a CB750A that needs a fuel petcock my current one has sat for 30 years and leaks. Does you petcock still hold fuel?
#20-0105
#20-0106
These adapters from
http://www.partsnmore.com should work, and were the ones we discussed by phone!
If you're looking for OEM, this is from my local honda store. Was kicking around and asked them if they can look it up for me today
16950-405-831 1978 CB550K
16950-405-831 1978 CB750A
16950-405-831 1978 CB750K
16950-410-015 1978 CB750F
16950-393-015 1977 CB750A
16950-410-015 1977 CB750K
16950-410-015 1977 CB750F
16950-393-015 1976 CB750A
16950-341-671 1976 CB750K
16950-341-671 1976 CB750F
Those are the part numbers for full petcock assemblies....so basically look for a 78K or 78K (CB550) petcock as they'll be the same as well.