depends on engine setup and how and where you are riding, it can do a pretty good day of trails on a tank of gas, a stock motor that is, you are fine for hairscrambles
I have a stock motor with fmf fatty and pc2 exhaust no airbox and running a 290 main and I can go 3 hours hard in the dunes on the pipe all the time and imm running dry on the road back to camp and have to hit the reserve I would guess a minimum of 28 miles of beach riding plus dunes