Your gauge may be reading correctly with the problem being in your petcock. We have always put in at least 4+ gallons when running the tank after the fuel light comes on.
The Light works on diagnostic so I'm thinking it's a connection issue... The bike had 6200 miles when I got it and ran out of fuel at 6800 miles... I did turn to reserve and made it to a gas station... But I think I'm gonna try the carrying a gallon of extra fuel and running it dry...
I have a fuel mileage and capacity update and photos to post later, but right now I wanted to post something that shocked me a bit.
We ran an extended trip on Saturday so I could run the tank dry (it was full). I need to pull the tank to replace the throttle cables as well as take some pics of the vents etc. for members who haven't had their tanks off before.
I also wanted to see how much fuel I could squeeze back into the tank now that I've drilled the holes in the filler neck.
Despite my best laid (but ineptly executed) plans to arrive home from a 440 mile trip on fumes, I actually had well over a gallon remaining so had to plan a side trip yesterday morning (Sunday) to burn that last gallon or so. MapQuest showed my little lunch run being around 44 miles round trip (a run down the freeway and back).
To my surprise, despite the fuel gauge showing just below 1/4 tank when we got home from our Saturday trip, I was only a few miles from home on the way to our lunch destination and was surprised to look down and see the low fuel light on.
I kept an eye on it, thinking maybe I'd been on an incline or something to set it off, but it continued to stay lit, with the fuel gauge wandering between below 1/8th tank and E. I hadn't yet reset the odometer from our trip so noted it was at 450 when the light came on. I was confused about how much gas was really still in the tank.
So I took a remote desert highway down to lunch instead of the freeway, into a strong dry desert headwind. I was waiting for it to run out of fuel so I could switch to the reserve tank and note the mileage.
So I waited. And waited. And waited, beginning to wonder if I'd had it backward all along and my petcock was already set on reserve rather than the main
tank. 20 miles later we arrived for lunch.
I pulled the fuel cap and looked inside and sure enough it looked like it probably still had at least a gallon inside. Went in for lunch before heading back home to catch the end of the NASCAR race, which I nearly missed because we made an unplanned stop at Speed Vegas where you pay to drive luxury sports cars on their race track (Ferrari, Lamborghini, Porsche, etc.).
3 miles up the same remote highway, this time with the wind at our backs, the fuel ran out and I switched over to reserve without issue, the motor firing right back up at highway speeds. I used to do that all the time with my last bike.
I looked down at my odometer and it read 475. The bike ran A FULL 25 MILES after the fuel light came on, BEFORE having to switch to reserve. I couldn't believe it. We ran another 15 miles home. We were probably running around 60 MPH 2-up on that lunch run, mostly into a strong headwind on fairly level pavement.
So just now I opened up the fuel lid and looked down with the bike on its side stand and the right side of the tank is DRY. I stood the bike up and jiggled it a bit to allow the fuel to level out on each side and stuck a tape measure in and it's about 1/2" of fuel. I'm guessing there's about 1/2-2/3's of a gallon left inside. The bike's been getting over 45 MPG riding 2-up.
I'll come back later today or tomorrow with an update after pulling the tank and filling back up to the drilled holes to see how much fuel the tank will actually hold with the filler neck mod.
Anyone else clocked the mileage between their light coming on and having to switch to reserve? Our gauges are likely all a bit different but having this knowledge is a plus for me. I'll know that I'll safely have 25+ miles of riding after switching to reserve, and 50 miles from the time my fuel light comes on.
With the bike on the side stand. No visible fuel after 15 miles running on reserve.
Bike leveled out, about 1/2" of fuel showing inside.