I've done a little bit of research on this issue. I won't swear that this is totally accurate but when my light comes on I have 1.3 gallons left. When the last bar on the gouge goes away, one gallon left. I don't trust it with my life. When I got my bike I had read that the tank 5.3 gallons. Not so, 4.7. I ran out on a trip, it took exactly 4.7 to fill it. I don't get it, this bike averages 40 mpg, my V7 does better than 50 mpg yet has a 5.5 gal tank.