For the life of me I can not get my 450 to idle, if I keep the choke on just a "little" it will idle. I take the choke off, it will idle for about 10 seconds then it will kill. It is also backfiring when decelerating.
do you have any mods or is this 450 completely stock? sounds lean if it runs better w/ choke ON. but then it would more likely backfire on acceleration. anyway... check for an intake air leak. are your bands tight around your insulator(front of carb) and your connecting hose(rear of carb) to air cleaner. check fuel tank breather and carb air vent hose. float level could be low or clogged fuel line. these are just some things that could cause a lean mixture. again, i don't think it's a rich mixture prob. when did prob. start?
oh yeh... has anyone touched your mixture screw? i think it should be 1.5-1.75 turns out from factory. you must turn it all the way in first though, but not tight. hope this helps... keep us posted schindog. did you get your lights off yet?
i forgot to mention earlier... if you just bought your quad, the first thing you'll want to get before anything else is the "service manual". i didn't even perform my first oil change w/o it. i see them on ebay all the time.