YFZ470 with a J&E 13.5:1 piston, Alba system with box lid off..I've been playing with the jetting and I'm curious what most people find to be best for the dunes...I currently have a 50 pilot and a 170 jet....Seems to be a little lean up top..

 

Lucky........

 

Sounds like it would be very lean at the dunes in the winter. I would think something close to a 180 or maybe 182 on the main jet. My stock YZ426 runs with a 172 in the winter. The dunes are around 500 feet elevation.