78 cb550 carb leak... HELP

[curby]

One thing that I caught when I did my PDs:

If you didn't replace the float valves they need to be cleaned, by that i mean taking brake cleaner to the spring loaded plunger in them and make sure they spring back quickly and freely. If those are gunked up then no matter how good the floats are set they'd always be open (or closed)

Yup cleaned and plungers are working as they should.

Have you checked that your floats actually float in gas?
The float moving freely in the bowl? Blow into the "in" line, then turn the carbs over, you should not be able to blow any more.
My vote is the needle/seat combo. They are matched and should never be put back in different positions. Also it doesn't take much to gunk them up.

Yup, took floats out and soaked them overnight and still floating in the morning. even submerged them overnight and they still popped up in the morning.

floats move as they should, no binding or sticking whats so ever.

float valves are clean and shut off when the floats pushed ever so slight to start pushing in the plunger.

???

I am double checking to see if it leaks on the center stand. gas has been on since 6:00 this evening and it is now 11:00 and no leak... but i bet in the morning there will be.... we shall see.

 

[curby]

Ok. Checked at 12:30 no leak. Go out this morning... Overflow tube is full. ?


So from 6pm to 12am no leak.

Check at 10am overflow tube is full of gas.


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[surffly]

How do you know its full?
Wouldn't it just leak out as it should?

You have checked that the tube itself isn't broken?
Really sounds like a worn needle/seat.

 

[curby]

W

Identification marks for anyone that can help.


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[curby]

I attached a clear tube the overflow nipple.

I'm thinking the float valve may have a tiny imperfection and there's a very small leak. Hence way it's taking so long to show up


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[surffly]

That I perfection could be described as worn.
Changing the needle seat or float valve as I think you are calling it solved my issue.

 

[curby]

The needle goes into the valve to shut off the fuel. The needle is fine but the valve may need work. I wish the were replaceable. Damn it.


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[surffly]

We might be having a terminology issue.
The needle and seat are a matched set.
They are a wearable item and replaceable.
Many people look at a needle and don't know when worn is worn. It's very subtle

 

[teazer]

I'm not sure if I got your symptoms correctly but leaving the gas on overnight will make most carbs weep slightly. If the gas tap was "off" then it's probably letting some gas leak past.