So I'm sure there is a logical explanation for this phenomenon and I hope somebody can explain it to me in semi layman's terms. So here's what happened. I love to ride up around the 6000-7000 ft elevation, since I live fairly close to the Giant Sequoia National Forest. I have taken my KX 250 up there in the past and my bike ran beautifully. Probably could have been jetted and dialed in for those conditions but that is beyond my skill set. Basically I'm a rider, that can change the spark plug, clean and oil the air filter, change the crank case oil and that's pretty much it, so messing with the Carb screws is like cryptonite to superman for me. Anyway, my question is why would my bike run fairly well at that altitude 4-5 times, then all the sudden the last time I took her up there, she flooded, bogged down and finally died on me, while spewing large amounts of gas out of the overflow hose. even with the bike off, I had to turn off the gas to get it to stop. Took it back to the camp ground and loaded her onto my truck thinking I was gonna have to put her in the shop, then brought her back down to the Central Valley in Cali, which is about 350 ft above SL, and she ran fine once again. No sign of any problem at all. So can it be assumed that it will happen again the next time I try to take her up?