I have an 06 WR450F. Removed air restrictor, cut grey wire, pulled some junk out of the pipe. Runs great down here at sea level. I am taking it to Ouray CO (altitude 10,000 ft?) later this month. I asked the dealer what I needed to do to re-jet it for altitude. They said to bring some different size main jets - so I got three: 158, 160 and a 162. So I was playing around with the carb yesterday and pulled out the main jet. It says 165S on it. So here are my questions: 1) Do I need to change anything else (besides the main jet) when I get up to altitude? 2) I got the main jet out with a 6mm socket with the carb on the bike - do I need to pull the carb off to change the pilot jet? Any other suggestions for a carb neophyte? Thanks.