Air in my fuel line.......

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Ok this problem is driving me ape sh*t.  I am apparently somehow getting air  in my fuel line.  Things I have done are:

-Replaced the petcock with a f450? petcock as per this site
-replaced the fuel hoses with clear ones in an attempt to see to problem happening
-replaced the spring hose clamps with fuel injection worthy screw type hose clamps of the correct size(sized for 11-13mm)

No gasoline seems to be leaking from the bike(aka. no puddles).  If I let the bike sit, like over night,an air buble develops in the lines just to either side of  the petcock in it also.  If I run the bike the problem is exacerbated and the air bubble get bigger until it eventually starves the bike.  I have also tried to reposition the petcock to allow any air that may accumulate to rise to the tank to no avail but thats  just a band-aid fix anyway.  This originally began happening with the original petcock, thus its replacement but every thing I try is not fixing th e problem!!  Did I really have a bad petcock and buy a bad one too?
I ride a '93 with essentially stock everything.

Thanks

[Flanders]

Any chance you have a clogged vent?

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Since I have been trying to figure this out over several months I am not positive, but I believe I have run the bike with the fuel cap open and still have the problem.  Also it happens when the bike just sits for several hours/days.  Thanks for the suggestion. 

[scottpA_GS]

Did you pull and inspect your carbs? Mine had an "un-solvable" starvation problem, turned out there was a VERY small hole in one of the diaphrams 

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Granted its been several months since I took them apart but I did clean, inspect and replaced the gaskets as welll as the float seats and needles.  Also I don't see the connection of air getting in the line if the carbs are out of whack.  The bike seems to run fine until the air bubble gets so big that no fuel passes and then the bike starves of fuel.

Another bit of info is that the bike ran with no petcock (and no problems) while I waited for the new f45o one to come in.  I just used the tank mounted valve with a long rod to the opposite side of the bike that I could turn.  I had no reserve though and the log rod setup was difficult to turn given the angle.

[X-ray]

I just went and fiddled somemore.  I have made a discovery but do not know how to interprit it.  After replacing the fuel lines again I left the line from the petcock to the carbs long.  This caused a fall-from the pet chicken, rise-over the frame cross member,falll- just past the cross member,rise- up to the carbs,path of the fuel line.  An air bubble had become trapped in the first rise.  This means that the air/fuel vapor? is coming from the fuel line or the gasoline itself.  Maybe not unlike like soda?( I don't really think so but?)

I also pinched the line repaeatedly in an attempt to move the bubble only to have it grow!! At no time did I run the bike.

Therories? suggestions?

[simoniz]

I had a similar air lock problem after removing the carbs to rejet. So I ran in some fuel from a gravity feed dirt bike tank and it ran great, so I let it run a minute or two to fill the float bowls, then shut off, reattached the Suzuki fuel tap and lines, and it was fine ever since.

If I don't run the bike regularly, the fuel seems to evaporate, and I have to run it on Prime again, even after a week or so. The GS seems to be sensitive to this.