Hey guys I have a 2003 sportsman 700. when you first start it up it runs great, untill it gets warmed up. about the time the fans come on its starts missing and poping and throttle response goes to crap... I replaced the plugs and filters and still does it.. like I said it runs great untill it hits operating temp and then it all goes to crap.. it will still run its just misses and pops under throttle.. any ideas what this could be???

 

Check the adapter boot that attaches the carb to the head (intake boot). On the underside they are prone to crack. When they get warm the crack widens and they suck air under throttle. The bike will idle fine but cuts out when you rev it up.