What am I missing???

[Eastcoaster]

78 carbs brass floats
Problem # 2 carb leaking
I have 10 hours plus in this problem
No leaks if the floats are held up on the bench test without bowl and just a slight touch
Put the bowl on leaks like crazy
The float action is smooth no resistance

If I back off the 4 bowl screws and leave the bowl loose it will not leak all day
Tighten them back up leaks and leaks

Here's what I have tried
I have removed the gasket completely Leaks
I have bent the brass float 6 ways from Sunday no change Leaks
I have made templates up of the bowl checked sides front with the float on everything for clearance looks like lots of clearance
I have tried another non leaking brass float leaks
I have changed the bowl Leaks
As long as I leave the 4 bowl screws loose no leaks at all
My brass float has been adjusted so much I think I should start with a new one
I am at a total loss is there something I am missing?
Just beside myself on this one

[SFerinTEXAS]

Plugged vent?

[skids]

It must be something within the carb body. You did say the floats are free moving. I assume that means it isn't touching the side of the bowls or the gasket. Is the float pin sticking? Did you turn the carb bank upside down and blow into the fuel hose to check for leakage? Carbs can overflow on the bike on earlier carbs if the vent hoses are blocked. Just shooting in the dark here...

[Eastcoaster]

I have bench tested with gas upside down no leaks
If I keep the bowl down with loose screws on the gas bench test no leaks
The float moves freely just the slightest touch lift will seal
Changed the gasket it leaks
No Gasket it leaks
Drop the bowl a little no leaks

[Schming]

Maybe try switching needles around to eliminate one more possibility.

[Eastcoaster]

Yup did that with the # 1 carb and the needle seat Still leaks
# 1 carb fine with either one
Switched floats also
# 2 still leaks
1 3 and 4 are all fine

[Schming]

Gasket need trimmed a little more ?

[Eastcoaster]

Took it out completely Leaked

[motoman]

The 'slight touch' throws up an instant red flag. That #2 brass seat would be next suspect with moving movable pieces around and still leaks.

As for the bowls, when resting in recess correctly, they SHOULD have a bit of 'wiggle' in that recess before putting any screws in. Occassionally, I've had one bowl or another catch the edge of recess and only THOUGHT it was in recess correctly.

[Eastcoaster]

Switched the brass seat with # 1 carb Still leaked
Switched Floats Still Leaked

[DGXSER]

Look close at the bowls. I had one carb would leak kind of like that. On a set of early carbs. I had the float bowl from an 80-81 set on that one carb. Look close at the enrichment tube and where the holes is in the float bowl. They are off just a mm or two between the two carb types.

[Eastcoaster]

All bowls have bottom drain cap I think they are early version unless they carried bottom drain cap for other years?

[dpotter58]

I had the same problem with the #3 carb on a set of 79's. like you I fought it and fought it. the big phucking hammer I beat it with after picking up another body felt good.

[Ken Talbot]

Are you running one or more fuel lines to either of the upper "T" fitting between the carbs, which are in fact atmospheric vents on early model carbs?

Where the small contact end of the float valve needle contacts the brass tab, is there a worn spot on the tab that is causing it to stick, even just the slightest amount?

[DGXSER]

Yes, the 78 through 80 bowls gave the same drain plug. Look identical except that tube placement.