Fuel Overflowing

[Gearz]

I have fuel overflowing from 2 of my carb bowls. I don’t think it’s a problem with the floats, but maybe an issue with the metal tab that seats the needle to stop the fuel flow. Is that metal tab supposed to flat? Mine are all slightly bent upwards which I suspect may not be fully seating the valve.

[1978GS750E]

Those tabs are used to set the float height in the bowls. Reference the service manual for the correct float height for your bike.

[Gearz]

Thank you for the reply. I will check out the manual.

[Nessism]

Those float valve tabs should be flat, or slightly down.

[Burque73]

I have fuel overflowing from 2 of my carb bowls. I don’t think it’s a problem with the floats, but maybe an issue with the metal tab that seats the needle to stop the fuel flow. Is that metal tab supposed to flat? Mine are all slightly bent upwards which I suspect may not be fully seating the valve.

I just went through the BS34 carbs on my GS1100GK. It's a new to me bike, that wouldn't start, so I decided to do a full tear down, clean and replace O-rings. Use caution bending those tabs. A little adjustment makes a big difference. If mine were bent up as far as yours are, fuel would be pouring out too! You'll need to check the fuel height after making any adjustment. I think it's actually supposed to be checked on the bike, while running, but this is the best I could do.

Here are a few pics to reference.



If you tear down completely, it helps to be organized

20240914_155740 by Roger, on Flickr

It also helps to be super careful. The PO was not careful with my 850's float post

20190316_165352 by Roger, on Flickr

Measure float height with calipers FROM THE GASKET SURFACE

20241004_171629 by Roger, on Flickr

Bend the metal tang thingy accordingly. Bend the tab up (away from the needle) to increase fuel level, down (toward the needle) to decrease.

20241004_171706 by Roger, on Flickr

Measure again. I think mine was supposed to be between 21 and 23mm but check the manual....

20241004_171949 by Roger, on Flickr

With your temp fuel bottle in place, connect a hose to the drains (I placed a tub underneath to catch fuel, it gets messy so do outside if possible) The way I interpreted the manual was that the fuel should be within the thickness of the top lip on the float bowl. (between the bolts and carb body)

20241004_174411 by Roger, on Flickr

My fuel bottle (design courtesy of bwringer

Disclaimer: Not written by an actual mechanic. Any information, advice, knowledge, suggestions, ideas etc shared here could actually be complete B.S. Always read the shop manual!

[rphillips]

Hope nobody is confused. His picture shows the tabs bent "up", but the carbs in the picture are upside down. put the carbs on the bike and they actually are way down...The near one in the picture looks waaay too low, the next one over looks reasonable.... I think.

[Nessism]

Hope nobody is confused. His picture shows the tabs bent "up", but the carbs in the picture are upside down. put the carbs on the bike and they actually are way down...The near one in the picture looks waaay too low, the next one over looks reasonable.... I think.

With the carbs upside down, the tabs should be flat or slightly down. Tabs bent up means someone either doesn't understand how to adjust the floats, or some $hit aftermarket float valves were installed