Actually Whatyardwork is correct, use the odometer 140-150 miles better get gas just in case...I find that if my bike runs out of main fuel, the engine dies without any warning and I have to quickly pull in the clutch and coast to the side of the road. Really kinda hard to switch to reserve, while holding the clutch in, get the bike in neutral AND restart the bike all in one motion. Only happened once, now I do the 140-160 mile refill routine.
Not at all like my metrics which would lose power, but give you enough time to reach down and flip the valve to reserve before the engine died.