r/KTM • u/Chet_Copperpot • 1d ago
PROBLEM Jetting for high altitude
I just picked up a 2010 250XCF-W and it runs great at home roughly 5k feet of elevation, but when I took it to the mountains at around 11k feet it was extremely difficult to start and felt bogging in first gear once I finally got it going. Does anyone know if swapping jets would help and, if so, what size would be best for high altitude? Also I’ve heard that adjusting the fuel screw could help as well but I don’t have any experience with that. Thanks!
2
u/spongebob_meth 5h ago
You should already be jetted down pretty far at 5k feet, so make sure it isn't at stock jetting currently.
Yes you need to rejet to compensate for altitude. Those of us in Colorado can usually find a setting that works OK everywhere. You will need to adjust your fuel screw and idle speed as you climb, but as far as taking jets out and swapping on the trail, nobody does that.
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u/IlllllFan 1d ago
Yes jetting for high altitude will fix it. Also, it's super easy to swap the main jet, you don't even need to remove the carb. A Lectron is even easier.