Honda cb 750A Carb problem

[zonson]

I recently took my carb apart and cleaned and replaced minor parts with a kit. Problem was that when I was in LOW, since its a automatic, the bike would sputter and gas would leak like crazy through overflow hoses. I found one of the carbs where the float is to be full of gunk. Cleaned out and so forth,

Now I put it all back together and left the air filter off to make sure all was ok.




The carb closes to you in the picture leaks from those two brass holes inside that hole that leads to the air filter, The carb next to it spits out air or gas, it spits. Any clue?

[TOOLS1]

It sounds like your floats are way out of adjustment.
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[zonson]

How do I adjust them?

[zonson]

I ask that because I hadn't messed with them before. Plus really don't want to take the carb back off again but if it need be then : (

[TOOLS1]

For 1976 it is 14.5 mm, for 77-78 it is 12.5 mm.
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[zonson]

Oh and last, could it be the pilot screw needing adjustment, I did change those and didn't really pay attention to how they were

[zonson]

Wait what? Im not so sure of what all those numbers mean. Its my first bike and first time tearing the carb out.

[TOOLS1]

Do you have a manual? If not you can download the factory manual from the home page here, for free. It shows how to adjust the float. Those numbers are refering to how high the float sits from the base of the carb before collapsing the spring in the needle valve. Also those screws are supposed to have a very tiny washer, and O-ring on them. If those are not there it will cause a problem, since they are "fuel" adjustment screws. They should be set at. 76-1 1/4 turn, 77-1 turn, 78-1 1/8 turn.
I don't know what all you have done as far as cleaning, but I would recommend that you remove the float's, and jets (I have a thread in the repair section on how to remove the pressed in pilot jets) then find a shop that has a sonic cleaner large enough to hold the whole rack at once, and pay them the +/- $50.00 they would charge for the service. These carbs have so many very small passages that it is next to impossible to clean them with out a sonic cleaner.
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[zonson]

Ok so looked in manual and had a print out one, the floats I set at 12.5 the best I could, one or two might be slight 12.75 whatever. I did this for all the floats, the guy before me had them at 20 something and I was always having to turn my idle knob up and down.

Well I still have the same problem though. When I go to start the bike only my 1st carb leaks out of tube all others are fine. This however is stopping my bike from staying idle or even running. I ve adjusted the piton valves and still same problem. This time however the bike wont even keep turned over with choke (direct gas).

So could I just have a bad float in that carb or what? If need be I can take a small vid.

[shinyribs]

Are your floats brass or plastic? If plastic:check for cracks or dunk them in gas and see if the continue to float overnight or if they sink. If brass:do the same sink test or if they already have gas in them you can probably shake them and hear it inside.

It could also be a needle and seat assy not sealing properly.

[zonson]

They are plastic, I changed the needle, piston  screw and another screw, so I will try to take them off and re-assm. them. Will try the sink test also. Let you know what happens tomorrow.

[TOOLS1]

Try polishing the seats with a Q-tip, and chrome polish. Also I'm curious, is your accelerator pump working? Have you checked the rubber boots for cracks?
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[zonson]

I checked the accelerator thingy and it had some build up on its underside other than that It was clean. Im not so sure if by rubber boots you mean the rubbers that connect the carbs to the engine and also to the air box. If that's what you mean then YES, one or two are a mess. The bike is a 77 Honda cb750A and so far I haven't seen rubbers for this model. I read some where that the K model was the same for the rubbers but not sure. I was going to come on here and ask later, but since you brought it up Im asking now. Would the K modle rubbers fit my cb750A?

[TOOLS1]

If the rubbers that go between the carbs, and the engine are bad it will make the bike run like crap. Unfortunately they are not the same as a K, and are not available. You could replace your carbs with the old style roundtops. These are better carbs anyway.
The accelerator pump has several very small passages, and two very, very, very tiny check balls with springs that are almost impossible And since you are not saying how/what you did to clean your carbs I would bet that every passage (pilot, main, accelerator pump....) is still plugged. These carbs are VERY hard to clean!!!
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[zonson]

Oh to clean my carbs I broke them all the way down and replaces all that I could with what came in the kit, the pilot screw, needles and such. The thing with the holes in it, where the needle falls into, I cleaned all for with carb cleaner and sprayed the carbs out with cleaner also. As for the carb part, are you saying I should buy all new CARBS!? Last I checked they were ridicules in price.  

[TOOLS1]

Those passages are so small that spraying carb cleaner will not clean them out. Also most of them have turns that prevent you from poking a wire through them. I have tried cleaning these carbs by soaking them in carb cleaner for 3 weeks before, and the pilot, and accelerator pump passages were still plugged up. That is why I suggested you find a shop that has a sonic cleaner, and pay them the +/- $50.00 they charge for the service. I learned my lesson about this a while back.
As for replacing carbs, yes I was talking about replacing all the carbs with the old style (70-76) round top carbs. You can find good rebuildable sets for around $100.00, and new boots are available, for them, for around $75.00. Also your bike will have more power.
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[zonson]

Oh you just make my day. So honestly then this is my best option? well besides the sonic cleaning, but even with a sonic cleaning my rubbers are cracked. So then the new carbs are my best bet? If so could you give me an idea of what to Google and where to look. Right now studying for a math test (college, so more intense then H.S.) plus class starts in about 30 min. I had the bike running for a year and so many months that to run into such a problem as this, and being my first bike, seems... well the right words I cannot think of right now. But I do thank you for you help, I have been having to borrow and put gas in my parents car and truck since the bike was my only transportation. Plus money is not alux. no job. Well there is my whole week in a paragraph. : )

[zonson]

And just for a review, because Im still going to try and dis assembly the first carb and reclean and such to it. But the gas leak from the over flow tube was my main issue. But this whole thing tumbled down into something different. But if still the leak exist then my best bet is to replace the carbs all together?

[Lucky 1]

You need to get a Clymer's workshop manual.

It tells you haw to adjust the float levels.
But the float levels are probably ok .
You should check them though with a steel ruler or calipers.
The real problem is the float needles need replacement.

Also it will not run properly with the air filters off.

[Lucky 1]

A workshop manual is how you solve this problem.
It has photos and tells you how to do things.

Here is a good photo.