I have a 2006 Polaris Sportsman 450 with 150 miles on it. In really great shape. The carb was rebuilt after it had not run for 10 years. The carb was pretty bad. New battery, carb kit, fuel pump, fuel lines, fuel shutoff, fuel tank flushed and cleaned. Airbox cleaned along with a new filter. All intake air lines were open and clean. The ATV started right up after the rebuild. I took it around the yard without the airbox and it ran great great. Up a hill down a hill. Awesome. I put the airbox back on, buttoned everything up and and now NO power. Idled fine but bogging on acceleration and coughing and popping. Pulled the airbox, ran great. I'm about to pull the carb again and maybe I missed something in the carb. Anyone have any ideas?