I do NOT mean to sound like an ass by saying this but man, you gotta know how many miles you can go on a tank, use your "trip meter" so you know how many miles you've gone.
If ya run out of gas on a bike or in a car it's really silly and ya probably deserve it for "letting" it happen. I mean I'm SURE when someone runs out of gas they had to know there was a chance it could happen and I'm sure most think to themselves "I knew I should have added some at that last gas station I saw but didn't".
I've had my bike almost 3 years and have never even had to use the "reserve" feature....I just won't let it happen.
Anyway, lesson learned for ya and good luck next time !!
No offense and just sayin.
EDIT: I guess what I mean by this is unless you're in the desert where there's no gas for 200 miles, there's really no excuse....and in that event I wouldn't ride in the desert