Bad petcock?

[wilsonsandy07]

82 Gs1100ez

Long Time no post…

riding seasons back and so are my problems lol

just want to confirm with an issue, rebuilt/cleaned carbs over the winter and the bike ran fine with an aux gas tank gravity fed. Slapped the tank on, won’t run in ON. Runs in prime. Thing is I checked the petcock while it was off the bike with a hose and it pulled fuel when sucked.

anything else I could be overlooking? As far as I can tell there’s no other vacuum leaks of any kind on any of the boots, airbox, etc.

[1978GS750E]

Check the simple stuff first! Is it connected to the correct vacuum port on the carbs? Is there a hole in the hose? Do you have vacuum on the hose when it is not connected to the petcock with the bike running?

[rphillips]

A guy came by a few yrs back with the same problem as you. Told him only thing I could imagine was a vacuum leak. Quick look found his 40 yr. old vacuum hose had cracked right where it plugged onto the pet cock and fell off. trimmed and reinstalled and all was good. You already said you had sucked on the petcock vacuum inlet, and it was working. Like with him, first be very sure you have no kind of vacuum leak between carb and petcock. Other vacuum leaks on boots nor air box should have no effect on pet cock... of course my opinion. Yes, plus what he ^^^^^ said.

[wilsonsandy07]

I did put a brand new hose on, but looking at it now it’s slightly long and forms a bit of a horseshoe. I’ll trim it down a bit and see if that helps at all