So I'm thinking you are talking about the tank=>vapor canister, yes?
I would say keep that in place, and even if you remove the canister (which we all agree is ecologically bad - not judging, just saying) you still need a way to vent the fuel tank.
Now having said that, our OEM fuel tank gas caps are venting as well, but they are configured to vent at a higher pressure, which means that they are only active when enough pressure builds up in the system that it approaches an unsafe level.
I say all this b/c this is where I'm coming from:
1) I have the tank=>canister line hooked up on my ride
2) I have the carb (TQ)=>canister line hooked up as well
- this does in fact work b/c with the correct fuel bowl vent setup it will prevent your carb heat-soak from pushing the fuel in the bowl fuel out of the idle/booster discharge ports, thus making for a nasty hot re-start
3) I do NOT have the canister=>TQ purge line hooked up
- which essentially means the canister is kind of a storage box for gas fumes, nothing empties it, but it also prevents that "whiff of gas fumes" hitting your face when you pop the hood open
- I do occasionally worry if I'm creating a little "explosion ready box" there, lol, I mean I think the bottom filter is slowly allowing the fumes to escape out, but I've never tested this, so maybe at the start & end of a cruising season I should actually hook the purge line up and just vent the snot out of that thing????
Does that help?