Jason Weigandt gets an update from the Monster Energy 450 Supercross Champion.   Chase Sexton could or even should be turning into a diva now that he's been a championship contender and race winner consistently in the 450 class, but instead, he seems to become more open, more accommodating and more friendly with each race win. Jason Weigandt chatted with him late last week for an update on Pro Motocross testing and prep, how his championship weekend went in Monster Energy Supercross, and why he's still humble (hint: midwest roots, says Chase).    The Racer X Exhaust Podcast is hosted by Jason Weigandt and sponsored by Yoshimura, Leatt, On Track School and the WD-40 brand. Also, be sure to visit RacerXBrand.com and check out our summer line of apparel.