My buddy pick up a 2000 xr4 Al Baker edition. From what I understand it's a beefed up xr4 with a fcr39 carb on it. We cleaned it up got it running and starting good when warm runs like a champ. But man it's a bitch to start cold and we can't figure it out. I'm thinking jetting because he bought it at sea level and we are at 4600ft. What would be the correct jetting for this altitude. I think these are 440 bore with big gun exhaust and unit filter. Any help would be appreciated thx.