Extended Run Gas Cap
Years back, before the introduction of the "extended run" cap, I had a Honda 2000i, and faced with that problem. I resolved it by ordering another Honda Cap, took the insides out, drilled a hole thru the top to insert the hose, and sealed the hose around to prevent air - worked for years. i evently bought the metal one. You can look at yours, go to Northern and get a cap and make what you need.