79 GS550L odd fuel problem

[abefroman]

I've been working on my 79 GS550L for a few months now. I recently painted the tank, rebuilt carbs, fixed the fuel level unit, etc. After derusting the tank I assembled everything and tuned/synched the carbs. Everything was running great with my temporary tank. When I installed the actual gas tank, It will only run with the choke lever up 1/4 of the way and dies when given gas. I ordered a new petcock thinking that was the issue. This morning I decided to take the gas cap off and try it and it runs like a champ.


Any ideas what could cause this?

[tkent02]

The gas tank vents through the keyhole, some how it has gotten blocked.

Not sure exactly how it is on your L gas cap but look there.

[abefroman]

Thanks,

I'll give that a try