All due respect to the Pumpless amongs us......... I reinstalled mine , like the look of the bit of Chrome on the left side personally , but that was not the reason .
I drilled out the vent and installed the Suzuki Needle valve , but I found the Bike ran fine on the top of the tank , yet noticably lean on the lower 1/3 . And I discoverd why ... when I checked the float level with the Fuel pump installed and turned on , the Level in the bowl was actually higher by a couple of mm than pumpless . The( mine anyway ) Bike just runs more consistenly and cooler with the pump installed and I never get the dreaded Carb Puking . Kury high 5 Air System , ported , stock Idle Jet , 175 main(Mikuni ) jet , Kury Needle on First clip from blunt end . pms out 2.5 turns . Cobra 2 into 1 exhaust , AIS removed . Running great , good mileadge , good Idle . ( Slow when bike Cold , faster after good warm up )
For what its worth .