77 Honda CB550 gas leak

So this is kind of odd and strange when I fill gas in my bike It runs fine and doesn't leak . When I go to bed I come back to fine a puddle of gas under the bike the next morning. Keep In mind it doesn't leak while I'm riding it or anything just when I sits .


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Are you shutting off the petcock when the bike is not running? If not, it needs to be switched off.

Leaky float valve most likely, or an o-ring on one of the float valves.

Here's what I would do:
-pull the carbs off the bike.
-put them on your workbench, use a couple blocks of wood to get them stable and level
-hook a fuel line up to the carbs
-use a fuel bottle and introduce fuel.
-wait and watch. Fuel will likely start leaking out of the overflow of one of the carbs, or back out towards the intake of one of the carbs.
-disassemble said carb and look for your problem.


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Also when I shut off the petcock It leaks out of the pet cock like out of of the actual knob. Do I need a new petcock??


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Probably just an o-ring.


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Does any one know where I can buy a new petcock????


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Here's a reproduction petcock from 4into1.com:
http://4into1.com/fuel-valve-petcock-16950-300-020-honda-cb350f-cb500k-cb550k-cb750k/

That will fit my 1977 550 super sport four ?