Gasoline vapor recovery system

Hello guys,
my GRiSO (US model) doesn't have the vapor recovery system because the previous owner removed it, so I connected the gasoline vapor hose (the one on the right of the tank) to the T-connector with the hose that came from the left of the tank and with the hose that goes to the back of the GRiSO under the CARC.
But now, from this hose I can smell gasoline scent and also when the weather is warm I can find gas and transparent oil drop under the GRiSO.

Do you think I should install a pressure valve? Now I don't have it.
The valve I'm talking about is the one you can find over the rear brake reservoir tank on every US GRiSO.

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bump

Thanks for the bump Keenerkeen07
I can smell gasoline also from the tank cap, I think the gasket is worn and it doesn't seal the tank anymore.

But the tank cap seal is not available as a spare part, here I can find a new one?