So I know this has been hashed over repeatedly as there are other threads about it. What size tank do I really have? 3.8 gal. or 4.2 gal. ? Im told by very good mechanics its 3.8 gal. on the center fill tanks. You wont get 4 gallons of gas in it. What about the side fill tanks on the fxlr and fxr2, 3 and 4?