Topic: CB400F Fuel Lines

[Vampire]

Am restoring a 1975 CB400F and was about to attach the air box to the carburettors when I noticed that there was not much room to fit the fuel tubes, so though that I had better do that first. Then I noticed that there are THREE pipes, two bronze and one silver that swivels (see attached photo). None of the parts diagrams or service manuals show a tube connection for that pipe, and I can't identify it in the parts list.
Can anyone tell me what attaches to that third pipe?
If it is a tube, can you provide the part number and/or tell me the dimensions of the tube and where it goes to?
Many thanks.

[Simon]

Can't help with the part numbers but I can tell you this. The two brass nipples are air vents. There should be two tubes connected to them going to the right of the carb and down between the frame and swing arm. The bigger nipple is for the gas line. 1/4 inch clear tube on my 400f. Yes, best connect those hoses while you have the space to work in.

Simon

[Vampire]

Thanks for that Simon.
That being the fuel line that attaches to the fuel tap, it is part 17681-377-000 but on the parts list, is one of the occasions where the Honda chaps omitted to provide dimensions.
I am restoring the bike from several boxes of parts, the parts list and service manuals, and without much in the way of practical experience, so some of these apparently simple issues can be a challenge when working from the documentation.