23 gallons?! Wow! My original tank behind the seat is only 13 gallons. Even carrying a 5 gallon Jerry can only gives me 18 gallons. At 13-14 mpg that’s aprox 230 miles driving the interstate. I usually stop for gas every 200 miles. My gauge bounces around so much it only gives me an aprox idea of how much gas is in the tank.
But in response to the original problem... I did the sanding of ground points with no luck. Turned out the bezel glass wasn’t seated properly so once I fixed that my problem went away.