float bowl gasket leakage

[pouchy750]

I have taken the carbs off my 1979 CBX1000 because they were leaking. One of the spring loaded needle float valves were stuck.
I thought this was the problem, but upon freeing the valve & reinstalling the carbs, they are still leaking.
I also reset the float height to 15.5mm as per advice on this forum. Thanks.
The valve needle tip & seat appear to be OK when inspected closely.
The carbs are no leaking out the overflow tube & pipe.
The carbs appear to be leaking from the front area of the float bowl / carb mounting surface.
I replaced the carb bowl rubber gaskets with new ones from Tim's. They came with the unassembled bike when I bought it.
They don't appear to be as thick as the originals, but that is difficult to really see because the old ones had silicon sealer on them.
Looking at photos on this forum, when the carbs are installed on the inclined engine, the actual float fuel height appears to be above the float bowl top surface, level with a mounting screw. Is this correct?
If so, should I be putting sealant on the float bowl rubber gaskets to stop them leaking? Or is there something else wrong here?
Thanks

[daves79x]

You did everything right - the installed float height means the fuel level is even with the front mounting screws, as you describe. But it is not likely the bowl gasket is leaking, unless you pinched it. More likely is that the O-rings on the fuel joints between the carbs are leaking and running down to where it seems like the bowl gasket is leaking. In all this you need to make sure the bowl drains are all open and the plumbing away from them is also clear. I've seen many bowl drain hoses plugged and it was overlooked.

Dave

[pouchy750]

Dave
I've just deleted the previous response, it made no sense when I went back & revisited the overflow tube layout.
You were correct, It would appear that a seal is leaking on one of the fuel line interconnections.
This carb strip down appears to be getting more complicated than the engine rebuild.
Thanks

[daves79x]

You are missing something. With the screw turned fully in, the gas in the bowl won't drain out the bottom to the drain manifold. But gas will still flow out the bottom drain if the bowl overfills. The standpipe drain bypasses the closed drain screw. You need to take a bowl off and study how this works and make sure something there isn't something plugged. Otherwise, see my earlier comment.

Also, don't assume you fixed the sticking float valve. Lots of them that were frozen will free up, but many of those will still leak gas. Wet test them for several hours to be sure.

Dave

[pouchy750]

Dave
You were correct, It would appear that a seal is leaking on one of the fuel line interconnections.
This carb strip down appears to be getting more complicated than the engine rebuild.
Thanks

[daves79x]

I don't recall if you mentioned it, but did you do a complete carb rebuild - separating them to install new O-rings, etc? If not, that's what you are in for now. None of these -now 35 year-old carbs with original O-rings can be trusted - they need replaced. Shout if you get stuck.

Dave

[whatscooking]

Same thing I just had to do sounds like. Gravity brings the leaking fuel to the low spot. Reach in there with your dry finger and try to wipe as high as you can around the fuel tubes and you will find the leak, mine was between 2-3. In my opinion if you have the ability to remove the carbs you can do a rebuild. Get the kits and the book. I have only done one set so I am far from an expert. And do a bench sync after the overhaul.

[Larry Zimmer]

As Dave said, likely the goring's on the fuel tubes. Be certain to get Viton mm material replacements. Much better temperature and ethanol resistance.