79 GS-750L spewing gas from carb 3's overflow

[Guest]

Hi,

I took the carbs off and tweaked the float heights to try to fix an overflow problem specifically on carb 3's overflow tube. I believe I made it worse and will need to pull them off again but am unsure? Once the bike is very warmed up it won't dump gas out the overflow but to get it ideling I'll have a huge spot of gas under the bike and a ton of smoke out my right exhaust.

My petcock seems to function with only pulling gas when vacuum is applied.

Does this sound like a serious float height problem or possibly the petcock?

[78550GS]

Sounds like you need to do a complete teardown on the carbs. Needle sticking.

[8ball]

You need to replace the float needles, for sure. And depending on how dirty they are (and if you are having other performance issues from the carbs), you may need to do a complete rebuild. The current Ethanol mix gas is horrible on the rubber tip of the float needles, if the bike sits for a long period of time with gas sitting in the bowls.

[cor]

I had one float needle that moved in the carb fine but the spring piece on the float needle required some cleaning. I think they are ok but I'll check again.

I'm also trying to find a good picture in a tutorial of the VM carbs on how to set the height correctly. I have a feeling they are so out of wack that it isn't even getting high enough....or maybe they are in upside down. Is the little tab there to hit the carb body?

[allojohn]

http://www.mtsac.edu/~cliff/storage/gs/GS750_Service_Manual_early8valve.pdf

Page 18 in the manual / page 22 in the PDF. Information on float heights varies ~ I think you need to be at 23mm + 1mm.

[cor]

http://www.mtsac.edu/~cliff/storage/...arly8valve.pdf

Page 18 in the manual / page 22 in the PDF. Information on float heights varies ~ I think you need to be at 23mm + 1mm.

Thanks for the link!