I had to burp it 4 or 5 times to get the 5.1 in the tank.

 

Per federal law, the stated fuel capacity has to be the amount of fuel it holds, not just the "size" of the tank.

 

I regularly ride mine past the low fuel mark and on every vehicle I own I run the fuel down to where I know my real range not what computer says. I have already put in 5.7 5.8 in my several times on my 08 RG I ran out of gas as I approached station coasted in it took the whole 6 gal. So in my experience it is 6 gal useable fuel

 

I pushed my luck on my new 17 RK and ran out of gas 3 blocks from the station. It seems that the "idiot" light comes on at 60 miles left. I filled up once right after it came on and it took 4.3 gallons. When I ran out, I had the LO RNG reading comes on with about 10 miles to go on the RES count down. Darn if it wasn't right. I ran out about 10 miles later. It seemed that my 09 RK was a bit more forgiving as I never ran out during my 50K mile run with it. My '17 has 2K on it and I have had to do the walk of shame once.