Buckeyebilly ... I've had my CRF-450 since June 2002, mostly ride the woods of Michigan, am an ordinary trail rider with no special skills. While I agree with the postings of the others who have responded ... I find that mileage is a poor means of assessing fuel needs as it is so dependent upon your riding style ... I am 56 and ride like you'd expect an old man to ride, that is I am steady on the throttle and tend to cruise the trials rather than run them in 'race mode' [i.e., hard on the throttle, hard on the brake, hard on the throttle] ... I have found that with mostly riding in first to third gear situations on reasonable trails at lower revs I can easily approach 42 to 45 miles on a full tank of premium gas which translates into motor operation time in the range of 3.0 to 3.5 hrs total. These are trails that have occasional deep sand portion, whoops, hills, mud and hardpack ... the main dependent variables under these circumstances seem to be the engine rev's and how hard the motor is working. Regardless, on such trail rides, I tend to keep track of the motor operation time and try never to exceed 3.0 hrs without access to refueling. Perhaps open trail riding circumstances such as deserts or firetrails are different, but I suspect that if you need 50 miles out of a single tank of fuel in the woods, you will want to increase your capacity by at least 0.5 to 1.0 gallon over the 2.1 gallon OEM tank ... and you might want to invest in a SenDec Motor Meter for your bike to give you accurate operating times ... not only does this device make it easy to tell how long you have been riding on a specific trail, but it is nice for keeping track of the important maintenance things like changing oils, filters, and the all important valve lash checks needed to keep your 2002 CRF450 purring like the happy cat it should be ... best twenty five bucks I have spent on my bike. Good luck & good riding.