what gets better mileage a 250 2t or a 450f reason im asking this is because im looking to get a new bike and i don't want to have to get an after market tank

Too many factors to really give you a good answer. It really depends on riding style, conditions, elevations, terrains, different brands, gearing set up, weight of rider, motor conditions, fuel used, etc.

Based on simple math I would say the 450f. My reasoning is this:
250 2t has one fuel charge for every two strokes of the motor, where the 4t has one every four. Granted there is a displacement difference but look at it this way: For every time the 450cc cylinder gets a fuel charge, the 250cc fuel charge happens twice, so 250cc x 2 = 500cc of cylinder volume with a fuel charge. I hope that wasn't too confusing.

Damian

ok thank you

I would say the 450 gets better millage, a friend and I both had CR 250's and then we went to thumpers, Anyhow we do a 20 mile loop and the 250 was always close to the end with some in the bottom of the tank for both of us, but now that he has the CRF, there is way more gas left in his tank and I don't remember how much difference in tank sizes there where but it wasn't much. since then we now do a 25-30 mile loop and never worry about the gas.

Dauntae

4t gets much better gas milage. But, the fun factor is definately with the 2t. I could not see riding anything else in the dirt. Long live the 2t!!!!!!!!

I can get 90 to 100 km out of my 08 kx 250 8.2 litre tank, and thats not putting around .

Yes the older XR,XT,TT600s engines get definitely a better mileage..., but the new 4 stroke engine generation are much thirsty and the mileage difference to the 2T is minimal.

I ride with several four strokes. A YZ450f, 2 YZ250f's and a KX250f. I can honestly say, I get way more out of a tank of fuel than they do, EVEN the 250f's. We are riding pretty equally, and I get approx 3.5 hours to a full tank, or about ~120KM's. Mind you, I don't know exactly how their bikes are jetted, richer jetting drink fuel faster :blah: :blah:

I always though 4T bikes always got better mileage than 2T bikes, but I guess it depends on the bike and rider.