I think I flooded my carbs

[AWRobinson]

I think I know my problem, but before I take apart my only transportation to fix it I wanted to run it by you guys.

Every now and again at speeds in excess of 85mph (especially going up hills) my bike startsd to lose power and I have to flip the tank fuel selector to "PRI" briefly to get it going again.  From what I understand this happens when the engine isn't getting fuel fast enough and you need to temporarily bypass the pump and just dump the fuel in using gravity. 

Anyhow, this happened a week or two ago cvoming over a pretty steep hill (405 S from the valley into LA) and I forgot to switch the fuel selector back from "PRI" after a few seconds.  So I rode all the way home with the selector on "PRI."  The next day I noticed my carbs had spilled fuel.  I also noticed that she doesn't idle anymore, I always have to give her a little throttle even after she's hot. Oh, and she backfires alot too. 

Reading through the forums, I believe my problem is related to flooding my carbs and somehow messing up my floats; but I wanted to see if anyone had a specific theory about what's going wrong so I can look for specific things when I open her up tomorrow.

Cheers!

[ajaxgs]

sticky needlels

[GeeP]

First of all, the GS doesn't have a fuel pump.  It is a gravity fed system.  The petcock is designed to flow fuel only when the engine is running.  The "prime" position bypasses this safety feature so that you can fill the dry carbs with fuel or bypass a faulty diaphragm mechanism in the petcock.

One of your float needles is sticking.  Imagine your float bowls and pools of gas.  The purpose of the float is to maintain the pools at a specific height relative to the jets which are immersed in the pool.  As the fluid level rises in the float bowl the float rises as well.  At the cutoff point the float forces a small needle to seat in the incoming fluid passage, cutting off flow.  If the needle sticks or is worn it will allow fuel to pass, flooding the carbs.  It will drain out the vent hole in the throttle body.  If the float needle is REALLY stuck (gas pouring out the carbs in a constant stream) you can generally seat the needles by gently tapping the carbs with a rubber mallet.

When you open up the carbs check the float bowls for deposits that could cause the needles to stick.  Dirt, sand, or goo will cause this.  Also check the needle tip and seats.  They should look brand new.  If the needle has a groove worn around the tip then it is time to replace the needles and seats.

[AWRobinson]

Awesome, I'll check it out tomorrow morning when I have time to get my hands dirty.

[RVertigo]

I thought the GS fuel system was vacuum fed...  Which is why you don't have to set the petcock to OFF.  Or am I 

[NiceGuysFinishLast]

I thought the GS fuel system was vacuum fed...  Which is why you don't have to set the petcock to OFF.  Or am I 

It is vacuum activated. Except when you set it to PRI, it's gravity fed. If the floats don't get the needles to seal properly, gas keeps flowing into the carbs.