I usually get my dad, who has a 2-up long track to strap a 5-gollon jug on the back seat, and we split the gas 50-50, I usually don't need it even on long trips because I have a 12 gallon US tank (10.5 gallons canadian).
As long as your riding with a buddy, just make sure one of you has a siphon and a small plastic cup/container. If one of you runs out of gas, you can always siphon enough gas from one of your riding buds so that you can make it to the next gas stop.
Just always try to be sure you know where the "next gas stop" is. 
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