Hello, congrats on getting a kdx 220..im sure you will end up really loving the bike..on the jetting, the honest truth on if your main is too lean or rich etc, is for you to read your plug..going off of what others run will get you no where..maybe a good baseline but everyones jetting can be different..the elevation, temp, air density, humidity, all effect it ,and then you have people with different exhausts, reeds, etc..so get a good reading on your spark plug.you can experiment with jets after you know it isnt lean..then pop in a few main jets up and down from 140 and see what feels best.and make sure it is a 140 for sure.a 140 is what i ran for that elevation when i had a 33mm carb on my 220..now i run a 35 mm carb though..and lack of power down low wouldnt be your main jet, you will be lookin at your pilot jet for that.if it's stock which is a 42 pilot, you can definately run a 40 pilot. as a bone stock bike, i highly reccomend getting a fmf gnarly pipe for it..then the power on top and down low will start pouring on!! mods on the bike can go on forever but stock kdx pipes are way too restrictive..fuel mixture, 40/1 should work fine..i run my 220 at 52/1 with golden spectro and love it..if you have any questions just reply on back,
Ryan