by JimDirt » Sat Jul 20, 2013 4:01 pm
The X is lean out of the box , even doing as little as removing the snorkel will lean it out more , it most likely has a #142 main in it , you need a #165 main to get it where it needs to be for your elevation , plus the newer X's have the smog crap , so that leans them even more than the older ones (05-06) , get a #165 and you will be good to go
This is a chart that was posted for me , by a Jetting Expert that posts here , this is his 450X jetting recommendations , you will note that none of them show a #142
Sea level 165
2000 ft...162
4000 ft...160
6000 ft...158
8000 ft...155
2020 CRF450R
2006 CRF450X

Weiser , Idaho