Just finished my second ride on my 450 & love it!! I changed a few things since the first ride - cut grey wire, Twin Air filter, Pro Moto exhaust insert. My question is, it has a hesitation from closed throttle. If you grab a handfull from idle it bogs, or in worst case stalls. Also noticed a small backfire occasionally, usually when cold. It runs fine when I'm up to speed, but was wondering if I need to tweek the carb a little. I am running stock jets and have not touched the fuel screw. I usually ride between sea level and 1500 feet. Any help appreciated before I make an easy fix a project from hell.