Strange Tubes - What is their Purpose?

[macxlii]

Working on a 1981 CBX which stood outside under a cover for some years. On removing the carbs, two pieces of rubber tube each with a rubber T- junction on the end fell out. The rubber Tees had rotted away and I had some difficulty in finding out that they seemed to fit between carbs 2 and 3 on one bank and between 4 and 5 on the other. The Parts fiche describes them as "Fuel Tube" and "Joint Set D" (Parts 13 and 27). The most puzzling thing is that I cannot figure out where the long arm of the tube goes and what it does when it is there (since they were not in place when I got there and the Shop Manual is not at all enlightening). Obviously, I'd like to avoid taking the carbs apart to install new tubes unless I have to. So, the question is, what are they?, where do they go? and what is the result of not replacing them?



Are they by chance are some redundant piece of Honda design (like the vent tube on the vacuum petcock which is better used as a tube tucked away neatly near the seat for blowing into to start fuel flowing before you crank up)?

[sr71cbx]

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[macxlii]

Thanks SR71CBX. Reassuring and saves me from splitting those carbs and upsetting all the settings. Looks like the topic as covered earlier in "Carb Hoses", guess I just fired off without looking. But appreciate guidance anyway.

[robertgood]

carb hoses
hi hope you dont mind me asking did you ever find out what the two joint set D hoses are for i am just going to split my carbs for the first time and before doing so i have watched several ideos on this but the only thing they didnt covet was the two t peice connectors between carbs 2 and 3 alos between carbs 4 and 5 they look like vent/breather pipes going nowhere the ones on my carbs have perished and i am finding them hard to get so i was wondering if i could just use a straight joint like between the other carbs, any advice would be appreciater, thanks Robert.

[shiskowd]

Welcome to the site! You're correct in that those two pieces are vents - each side of 3 carbs has a bowel vent between 2 sets of carbs that should extend with some additional hose to somewhere under the fuel tank. They are optional provided you don't ride in the rain or wash your bike. Replacements are available from a number of parts suppliers, one example is Randakk's:

https://www.randakks.com/cbx-air-tees-n ... CBX%2F1979

The other pair of carbs in each set have a simple bit of fuel hose connecting the carbs extending the vent to the 1 & 6 carb.

[CBX-tras]

Not "optional" but necessary to prevent dust, dirt, water, from finding its way into the float bowl.