Jetting for high altitude

[u/Chet_Copperpot]

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!