I have an IMS tank on my 650R. IMS's website indicates a 4.6 gallon tank. My tank holds 5.1 or 5.2. From a nearly bone dry tank I can easily dump in 5 gallons. It'll hold more if I fill it to the brim. Have they changed the tanks or to they "relax" and swell to a larger capacity over time? Just curious, how much does your IMS tank hold? BTW, it's a pain to get the last 3/4 of a gallon or so out of the left side of the tank. Sorta creates an emergency reserve after the petcock reserve, I guess. I've been getting 35mpg during my DS rides (175 main/68 pilot) so that gives me a comfortable 150 mile range and a 175 mile "oh-sh*t-I-took-a-wrong-turn-can-I-make-it-back?" range.