Author Topic: tubes missing from carbs (Read 4520 times)

txterror · « **on:** January 09, 2013, 02:57:55 PM »

I noticed that my carbs are missing these tubes that connect in between each other. I was wondering if i should try to replace them. Im in the process of trying to get the bikes intake system back to stock. Bought the bike with pods. What is their function and why would one take them off.

dave500 · « **Reply #1 on:** January 09, 2013, 10:49:32 PM »

taken off for cafe effect?
does the bike run?

madmtnmotors · « **Reply #2 on:** January 10, 2013, 05:08:20 AM »

Quote from: dave500 on January 09, 2013, 10:49:32 PM

does the bike run?

+1

Looks like the fuel rail. Without them there would be no place to connect the fuel line nor would the fuel be dispensed to all carbs. Pics of the actual carbs would help.

RSchaefer · « **Reply #3 on:** January 10, 2013, 06:05:00 AM »

+1

Yes you kinda have to have those they deliver the gas to the carbs. Maybe you mean the air vents for the bowls?

txterror · « **Reply #4 on:** January 10, 2013, 06:22:00 AM »

Bike does run, and im pretty sure its those tubes.

Scott S · « **Reply #5 on:** January 10, 2013, 06:47:25 AM »

Those are the bowl vents, right? The two hoses that just vent to the atmosphere.

RSchaefer · « **Reply #6 on:** January 10, 2013, 06:48:04 AM »

What bike is it?

flybox1 · « **Reply #7 on:** January 10, 2013, 06:50:27 AM »

Quote from: txterror on January 10, 2013, 06:22:00 AM

im pretty sure its those tubes.

guess again. bike wouldn't run without them. the circled one has the fuel inlet from the tank, the other 2 (there should be 2 without the fuel inlet) take fuel to the other bowls.

Deltarider · « **Reply #8 on:** January 10, 2013, 06:59:30 AM »

Quote

im pretty sure its those tubes

I'm afraid you are not pretty enough, so to speak.
Encircled is definitely fuel supply related.
I'd say what you're missing are the two smaller tubes that are between carb 1 + 2 and between 3 + 4 respectively (109 in the pic).They're for venting so air can escape when the float chambers fill. For some stubborn reason Honda calls them "tube fuel" as well ('tube fuel 2.5X16' to be precise).
Cf.: http://www.hondacbfour.com/download/pdf_spac/pdf_spac400/CB400_1.pdf

madmtnmotors · « **Reply #9 on:** January 10, 2013, 07:18:57 AM »

Quote from: madmtnmotors on January 10, 2013, 05:08:20 AM

Pics of the actual carbs would help.

txterror · « **Reply #10 on:** January 10, 2013, 08:13:10 AM »

Ill take pics tonight. If bike was running fine without them should i go ahead and leave it or should i try to replace them. bike is 1975 CB400f

Deltarider · « **Reply #11 on:** January 10, 2013, 08:29:58 AM »

I'd say they're not that essential. Dust or insects could enter somewhat. You could improvise something. Absence will NOT affect running.

txterror · « **Reply #12 on:** January 10, 2013, 09:30:49 AM »

Alrighty im gona leave it the way it is

RSchaefer · « **Reply #13 on:** January 10, 2013, 09:38:19 AM »

I was thinking in Hondaman's book there was a benefit in having the bowl vent tubes tied together, like balancing vacuum across the rack or something!

Deltarider · « **Reply #14 on:** January 10, 2013, 02:00:42 PM »

Quote

a benefit in having the bowl vent tubes tied together, like balancing vacuum across the rack or something!

I fail to see how... but that's me. As far as I know in the bowls there is plain atmospheric pressure and no pulsations.

flybox1 · « **Reply #15 on:** January 10, 2013, 02:11:12 PM »

Quote from: RSchaefer on January 10, 2013, 09:38:19 AM

I was thinking in Hondaman's book there was a benefit in having the bowl vent tubes tied together, like balancing vacuum across the rack or something!

the 'intention' is to create a slight vacuum inside the bowls, thus raising the fuel level 1-2mm. Its not the carb vent tubes....its the bowl overflow tubes, and they are not tied together. they are routed through holes into the airbox..

txterror · « **Reply #16 on:** January 10, 2013, 02:26:22 PM »

Ill take a pic when i get home

RSchaefer · « **Reply #17 on:** January 10, 2013, 02:58:15 PM »

You r

Quote from: flybox1 on January 10, 2013, 02:11:12 PM

Quote from: RSchaefer on January 10, 2013, 09:38:19 AM
I was thinking in Hondaman's book there was a benefit in having the bowl vent tubes tied together, like balancing vacuum across the rack or something!
the 'intention' is to create a slight vacuum inside the bowls, thus raising the fuel level 1-2mm. Its not the carb vent tubes....its the bowl overflow tubes, and they are not tied together. they are routed through holes into the airbox..

Your right now I remember!!

txterror · « **Reply #18 on:** January 11, 2013, 08:21:28 PM »

Heres the pic

flybox1 · « **Reply #19 on:** January 11, 2013, 08:34:07 PM »

. and you said the bike runs? Surprised it didn't start a fire.
Better get some fuel line on that bro. They are the fuel lines between carbs.

txterror · « **Reply #20 on:** January 11, 2013, 09:33:10 PM »

Runs fine besides the hick ups from the pods. Didnt notice any fuel any where

wowbagger · « **Reply #21 on:** January 11, 2013, 09:33:49 PM »

From your fiche it looks like the part your actually missing is #109. It's just about 1 inch sections of fuel line like flybox said. It's definitely a necessary part.

dave500 · « **Reply #22 on:** January 11, 2013, 10:46:42 PM »

your first post youve circled the wrong part,thats the fuel tee,just put some hose between those brass nipples,they vent between each other,dirt and crud will work its way in.

txterror · « **Reply #23 on:** January 11, 2013, 10:51:31 PM »

Yea i circled the wrong part. But was close. Lol sorry bout that guys.

txterror · « **Reply #24 on:** January 12, 2013, 03:13:19 PM »

can i just use rubber fuel hose?

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Author Topic: tubes missing from carbs (Read 4520 times)