Flooding

[desperado1971]

I have a 1981 cb750c. When I turn the petcock to open I end up with gas running out my overflow tubes. Is this being caused by the floats sticking? Or jets messed up. Just got the bike running and having a very hard time getting it to idle and stay running I think due to this. Just wanted some input and I’ll probably remove the carbs and try to clean them I guess. And should my petcock turn of all the gas completely? It seems to want to drip fuel even when turned off. Carbs will sit there and run all the fuel out of the tank through the over flow tubes.

[desperado1971]

Ok I took the carbs off and cleaned the bowls and jets. All appeared to be clean but did it any way. Floats were moving and seatting fine too. So why am I having gas run out the overflow tubes?

[Maz]

Either the float levels are too low,  the float needles are not sealing (clean and polish the needle tips and brass seats)  or the little brass overflow tubes, mounted inside the float bowls,  are loose,  cracked or missing.
Maz

[TOOLS1]

What he said ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TOOLS

[desperado1971]

The tubes are not missing and they are tight and don’t think they are cracked. Oh and I pulled the float needles and cleaned those too. How would I adjust the float levels? I appreciate the help.

[TOOLS1]

Bend the little metal tab on the float where the needle touches.
TOOLS

[desperado1971]

My floats are plastic. Don’t think I can bend them.

[TOOLS1]

Do they not have a little metal tab?
TOOLS

[desperado1971]

As far as I can tell the only metal part that is any where close to the float is the little rod that slides in to hold thm in place. Everything else is plastic. These may not be adjustable.

[Maz]

I just checked out some spare carbs for my '79 and you are correct - non adjustable. As the fuel only enters the carbs via the float valve though,  something is not sealing. Have the rubber tips on the needles gone hard?  Are the sprung pins on the end of the needles still 'springy'? Have any of the plastic floats split - Take them out and shake them to see if there is any fuel inside them causing them to sink.  Try leaving the floats in a bowl of fuel to check that they stay afloat.

Also are the floats fitted the right way up and are all 4 flooding?

Maz

[desperado1971]

I’ll check the springs and for cracks next weekend when I get a chance. Thanks for all the help. I’ll post back here soon.

[Maz]

Just to confirm, are these the floats you have?
Maz

[desperado1971]

Yes