fuel line check valve.

[jeepsteve92xj]

My Xingyue has a high mounted fuel tank and manual fuel valve - I replaced the original vacuum item. Easy-Peasy gravity fuel supply.

My Znen 150 has a low mounted gas tank, under the floor, and a vacuum operated fuel pump (original replaced with a Mikuni fuel pump because I felt like fuel starvation was happening when riding WOT for a mile or two)
But it is hard to start when it has sat for a few days. I think getting the fuel back up in the lines is the problem. A few shots of spray start and it will fire a few times before it will run on its own again.
So now I am looking for a small light duty gasoline compatible check valve to keep the fuel in the lines.
Does anyone have an idea of a source? Or other ideas to fix this issue?