Author Topic: cb400/4 carbs  (Read 1053 times)

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Offline steven400/4

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cb400/4 carbs
« on: July 19, 2012, 10:23:30 AM »
trying to set carbs on my 400/4 everythink new inside them number 3 carb when trying to set it the gage goes backwards as anyone else had this if so what was the problem ???
1978 honda 400/4 f2 my baby

Offline phil71

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Re: cb400/4 carbs
« Reply #1 on: July 19, 2012, 01:22:06 PM »
the gauge goes backward? Are you in australia?

oldbob

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Re: cb400/4 carbs
« Reply #2 on: July 19, 2012, 02:59:27 PM »
Could it be that you are adjusting one carburetor and reading the vacuum off of another? I ask because cylinders 1 and 2 are synchronized together, as are cylinders 3 and 4. When I balanced the carbs on a 400 using a manometer, I noticed that as I raised a slide (lowering manifold vacuum), the adjacent carburetor indicated a vacuum increase.

Once #1 matches #2 and #3 matches #4, you have to get the two sets to match each other. Patience helps.

Bob

Offline Bodi

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Re: cb400/4 carbs
« Reply #3 on: July 20, 2012, 07:29:23 AM »
Although 1 & 2 shares a lift lever as do 3 & 4, the balance adjustments are entirely independent for all 4 carbs. I suppose you could adjust the arms on the shaft and balance the two pairs as suggested, but these arms are keyed to the shaft as I recall and not really adjustable. Some other madel's carb stacks have one fixed link to the arm (non-adjustable) and you adjust the others to match, but the 400 has all four adjustable. It is still advisable to leave one adjuster alone and just change the other three, so you don't set all four way "off centre" which will affect the idle screw range and the choke cam setting.

Offline steven400/4

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Re: cb400/4 carbs
« Reply #4 on: July 27, 2012, 02:05:04 PM »
yet another problem i have no one seems to know why its doing it
1978 honda 400/4 f2 my baby

Offline camelman

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Re: cb400/4 carbs
« Reply #5 on: July 27, 2012, 02:20:22 PM »
Steven, I don't think anyone actually understood what you were trying to say. Your initial post wasn't very clear and was hard to read. Could you post a video or pictures to explain?
1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)