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250F's as altitude

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I have never ridden a 250F over 4,000 feet. Of course there was some power loss, but the bike was not unrideable. Anyone ridden at 7,000 feet or more? Does a 250F still get the job done? I know as a kid I could have ridden my XR100 at that elevation and not thought anything of as I would have been having too much fun to care. Sometimes I wish I still thought like that.

Greg

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Jetting is crucial anytime that you change temperature or elevation. The density of air changes. Whcih in turn means that the ratio of partivles of air to particles of gas has also changed. I have ridden my bike all the way up the 12,000 feet. Yes the bike loses some power, but not all that much. There is prolly even a few guys on here that have ridden up over some of the 14ers here in Colorado.

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I have never ridden a 250F over 4,000 feet. Of course there was some power loss, but the bike was not unrideable. Anyone ridden at 7,000 feet or more? Does a 250F still get the job done? I know as a kid I could have ridden my XR100 at that elevation and not thought anything of as I would have been having too much fun to care. Sometimes I wish I still thought like that.

Greg

I ride mine all the way over 14,000 feet. Most of my riding starts at 9K, and goes up into the high elevens. Power loss, sure, not running a moto at that elevation though so what do I care.

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I ride mine all the way over 14,000 feet. Most of my riding starts at 9K, and goes up into the high elevens. Power loss, sure, not running a moto at that elevation though so what do I care.

I am mostly concerned if the power loss is great enough that riders who regularly ride that high are wanting for more power. Sounds like that is not the case.

Greg

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I am mostly concerned if the power loss is great enough that riders who regularly ride that high are wanting for more power. Sounds like that is not the case.

Greg

No, just jet it correctly if your going to spend a fair amount of time elevation. When I ride up a 14er, the time spent at that elevation is fairly minimal, so I don't bother rejetting. I rarely have much issues in the inbetween numbers (9K to 12K), just have to be a little more on top of the motor to be sure not to get stuck down low in the powerband. I've got an '01 426 too, and still take the 250 on all my high mountain rides.

Dodger

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I'm 160 lbs and I don't race, but I do ride lot's of sand at around 5,000 ft. I find the power of a properly-jetted CRF250R is "sufficient", but not terribly exciting.

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I am mostly concerned if the power loss is great enough that riders who regularly ride that high are wanting for more power. Sounds like that is not the case.

Greg

I don't enjoy my dad's 250X at altitude at all. I think it's a dog. Sure you'll make it to the top but you aren't going to rail without keeping it wound all the way up.

At 5,000' you have around 20% power loss. It only gets worse from there.

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Another thing to remember is that a smoker will fatten up much quicker than a thumper as you go up in altitude. The 4 strokes are more forgiving in fuel to air mixture, so you can get away with a lot broader altitude range. :thumbsup: I ride from 5-12K, a huge range. The 250F is just an minor inconvenience at altitute, running a little rich, starts a little harder. Most smokers would require a jetting change. :applause:

Also, it 'feels' like the thumper does not lose the same horsepower per 1Kft as a smoker does (% fall off). Do others agree? :ride:

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