anyone out there replace the stock 3.5 gal. tank with a larger 5 or 6 gal. gas tank on a fatboy..?? i would like to get some extra riding distance without having to stop and fill up all the time... i have located some aftermarket tanks, they say they will replace my stock tank but... being that they are probably wider than my stock tank will i have clearance issues with my forks also will these aftermarket tanks be slightly longer than my stock tank so will there be issues with my seat..??