Question about 1992 Honda CB 750 Nighthawk

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Fuel leaking from carb vent tube on newly cleaned carburetor

I just stripped down my carbs, and gave it a good cleaning. Reassembled it and did a test drive. I noticed that there is fuel coming from the number 3/4 air vent tube that is connected to the carbs. Is the fuel leaking because the float valve isn't sealing? Do I need a new float valves?
Thanks for your help, Duc

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  • ducswing Jul 26, 2009

    How is the float adjusted? I didn't completely disassemble the carbs. The only o-ring removed was the bowl gasket.

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That would be either the float set to high or the needle and seat is missing an o-ring while you had it apart. Should look at getting a carb kit there only approx. 23 bucks and it would save you a lot of grief in the long run.

Posted on Jul 26, 2009

  • mike fuson Jul 26, 2009

    you can bend the float holder either up or down to some degree which would cause either to much fuel in the bowl or not enough. Check to see if the float moves freely up & down. Would be a good idea through if you put a carb kit in while you have it apart. Also when you take the bowl off make sure to cross torque it while puttting it together this ensures that there is no air leaks which could also cause over fueling.

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The bike is leaking fuel out of the left vent tube and if I tap the carbs with a hammer it stops temperarelly. What is the cause for this and would replacing the needles, seats and carb o-rings solve this...


sounds like the floats in the carbs are sticking.....need cleaning. as maybe some muck in them. or if been stood over winter they gum up!!.....i would give the carbs a good clean & strip down !st...

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