400 Rfs Mileage!!!!!!!!!!

[Coach in ND]

Does anybody know what an 400 EXC or SX can put on for mileage on a full tank of fuel. I'm heading to a local enduro this weekend and wanted to know how many miles I can put on my 400 SX before fueling. The SX is only 4/10 of a gallons smaller than the EXC so I was hoping to get 30 or so miles out of it.

Anybody have any experience with and SX RFS off road.

Thanks,