Charcoal Canister Delete (yes I've searched)

[nygged_out_GSXR]

Hey the gsxr1000 I got is a Cali model so it has the charcoal canister. Reference the following diagram: http://partsfinder.onlinemicrofiche....=13&A=296&B=40

Starting with item #1 it connects to the vent at the bottom of the fuel tank. Basically I deleted everything downstream of the hose listed as item #2 and routed that vent hose down with the rest of them.

Question is, what is item #4's (fuel shut off valve) purpose? Item #13 is a check valve (tank pressure control valve). Any reason I should leave either or both of these in place if I'm just venting the tank?