Found this in another post
https://faq.ninja250.org/wiki/Hose_r...ine_fuel_tanks
On the 49 state tank there's the one hose outlet (drain).
49 state models have only one hose coming from the rear of the fuel tank. This is a drain hose for fluid that gets in the depression between the filler neck and the top of the tank, from being in the rain or overfilling the tank. Air vents into these tanks
On the Cali tank there's 3 (L-R), with the middle apparently the drain.
The right tube allows air into the fuel tank through the gas cap as the gas level drops. This tube must remain open.
The middle tube is the drain and should keep the stock routing under the bike in the hose cluster (right-hand side of the frame, as discussed above).
The left tube circulates fumes to the emissions system and should be capped off.