250 2-stroke fuel efficiency

40-45 minutes.

Yup, normally 40-50 minutes max on a stick tank. Desert and trail riding about 40 miles depending on hill climbs and things like that

I go through a tank in about an hour on my YZ250. Usually around 3 hours I've gone through 5 gallons. So when I go on a two day ride at a track I have to bring about 7.5 gallons to make it through both days. Figuring about 2 hours of track time each day.

Last weekend I went on a 3 day ride with my 16 KX450F. I burned just under 5 gallons of gas and put 5.7 hours on the bike.

My friends son burned almost 10 gallons over that same 3 days on his YZ85. But that kid is the freaking energizer bunny. No idea how many hours he put on the bike as he doesn't have a meter.

Another agreeing with 40 mins on a two stroke. Once spent two hours riding non stop on track with a 250 four stroke and still had fuel in the tank when I stopped.

Four stroke I just brim the tank at the petrol station on the way and not care about running out. Two stroke it's filling the tank the night before and taking an extra two 5L cans of premix, and I've still run out.

Sounds about right, Turbojez...45 minute GP races are right on the verge for a topped off stock capacity 2T tank (in most instances)!

when i went through Mexico, i was getting between 25 and 30 mpg. that's high-speed and jetted very rich.

at home i'm getting closer to 35 mpg.

I rarely burn through a tank of gas on a practice day on my YZ125. If you're looking for fuel economy, there's your answer.

My 500af drinks it's 1.4 gallons in about 30min if you run it hard.

Actually , you're really not " burning " through as much as you think. A lot of fuel spills out the carburettor vent tubes while you ride, the more the bike is leaned over in turns, the more it see saws back and foward over rough ground and the higher your float level the more you spill.
It's actually the main reason why the epa has got it in for two strokes and an important reason why all the modern four stroke mx bikes are fuel injected.
KTM are claiming dramatic fuel efficiency gains with their fi two stroke...that's the reason why...mostly...

Greenies really , really hate the idea of straight liquid hydrocarbons even venting to the air , let alone spilling all over the ground wherever you ride..

I've heard the new lectron carbs on the 2 strokes really up the gas mileage. I'm looking at getting one for the YZ250 I built but have yet to pull the trigger.

Mix a stronger drink.

What do you mean?

what did that have to do with 2 stroke mpg?

He means your theory is ridiculous

2 strokes will always use twice as much fuel as a 4 stroke will. It's because of how the engine works. That's the main reason why the EPA pushed so hard against the 2 strokes.

My CR125 used about twice the gas as my 250F (fuel injected).

Well, actually I remember speaking with a friend a of mine who I can guarantee you, knows more than any of us about any of this as he now is a pretty important part of the r& d department of a manufacturer. We were talking back in around 2000 when the big scare was looming over the epa threatening the very existence of two stroke dirt bikes.
Yes two strokes use more fuel...that's a black mark, yes they burn oil and produce smoke ( dependant on a range of factors ) that's another black mark... But a very important black mark, the one that the epa was apparently likely to jack up over the most , was the constant spilling of raw fuel out of the carbourettor vent hoses, of which there are several , the one that leaks the most is the float bowl high level drain, which spills out raw fuel pretty much constantly when the bike is in motion on a rough and undulating track and frequently around corners depending on lean angle.
High float levels and or worn needle and seat would exacerbate the problem.
You might be quite surprised to find just how much raw fuel can be lost out of the vent hoses during a long Moto.
Next time you are at the track...have a look at some two strokes going by close up and see if yo can see fuel coming out of the vent hoses under the bike...
With the new KTM fuel injection system , that issue is completely iliminated , leading to much better fuel mileage , before you even get to the potential of fuel injection supplying optimally controlled fuel air ratios..

My friend said that this spillage ,presented a substantial problem as a complicated catching mechanism would be required and it would have to be capable of holding a fair bit of fuel.
That issue , along with the other black marks against the two stroke design hastened the development of four stroke bikes at that time , in that environment of the epa threat to ban two strokes.

Also the carbourettors used on pre fuel injected four strok mx bikes suffered less from the fuel spillage issues than the ones designed for two stroke bikes but I think I can be reasonably sure that the complete ilimination of necessary carburettor venting on fuel injected four strokes , played a significant part in their appeal to manufacturers , conscious of the ever pressing threat of stricter emission requirements...

In other words, the EPA doesn't like high carbon dioxide emissions due to high fuel consumption, and they hate smoke...but they REAlLLY hate straight liquid hydrocarbons vent to the atmospher or worse still...spilling all over the ground....Just Sayin....
Better go mix another drink

The difference in my fuel bill going from a 250 2 stroke to a 450 has been crazy. I use about £7 worth of fuel less each day of riding. Plus the premix oil worked out to be about £3.50. So that's a £10 saving on fuel alone each ride day going to a 450 4 stroke. Doesn't seem like much but when you ride 40 or more times a year it soon adds up!

With that being said, I still prefer to ride my 2 stroke!

Thats $10 you can put towards the engine re-build cost of your four banger bud.

Yeah, the 500 is insane on fuel