Help with a 1980 honda cb750 super sport, carbs leaking fuel out of the overflow tubes.?

Question

i know everyone is going to tell me that i need to check the float needes and seats but i did. im just wondering if it could be somthing else i purchased the carbs off of ebay and they have never been run on the bike befor. when i turn the petcock on the gas just pours out of the overflow tubes as fast as the tank will it. when you try to start the bike it will run for about a second or less and sounds like it is just flooded out. maybe somone could even tell me all of the steps to installing the carbs like all of the breathers and the like. thanks so much

Answer 1

I think you correctly ID'd the issues, maybe you got something internal to them wrong.

This wiki seems to cover everything I can think up.  Sorry, couldn't find pictures, but the author points to where to get those.

http://wiki.answers.com/Q/How_do_you_cle...

Answer 2

The drain screws can be loose (partially open), or leaking.

The over flow tubes in the bowls could have cracks in them.

Remove the float bowls and fill them with gas to see if they leak.

Adjust the float level -

Remove the carbs from the bike.

Remove all 4 float bowls.

Tie up 3 floats with rubber bands, so you don't make a mess while checking one at a time and hold the carbs over a drain pan.

Attach a fuel supply and turn it on.

Lift the float by hand.

The fuel should stop flowing when the float arm is parallel with the carb/float bowl mating surface.

Bend the metal tang that touches the float needle to adjust.

Repeat on the other carbs.

Answer 3

It can only be the needle and seat, unless you totally have them hooked up wrong, which is really hard to do. Sounds like either the float level is too high, the floats are leaking and aren't floating, thus not closing the needle, or either the needle and/or seat is just missing. This is a very simple circuit, identical in operation to how a home toilet works.  

Answer 4

tap the bowl with the big end of a screwdriver, always works for me :)