So my buddies 06 yz450f is having issues.... There is a huge difference in idle speed between choke and no-choke first of all. The idle screw needs almost constant adjustment to keep it idling with no choke. Also, he has an obnoxious decel pop, and it seems to have been running a bit rich. Where would we start with the re-jetting? What's up with the choke thing? Any help here would be awesome, Thanks!