Hey guys, I've searched the forum at length and can't seem to find the help I need. I have a 2003 YZ450F that I just got back from a local shop. I originally took it in because I tried messing with the fuel screw as it seemed to have a high, hanging idle. It still ran fairly strong, but just wouldn't idle. After adjusting the fuel screw in and out, and then back to the original position, it had no power and also bogged off of idle. I took the carb off, attempted to clean the jets and everything, and also replaced the spark plug. When I put everything back on, it wouldn't start at all . It would backfire occasionally, but never run. The guy at the shop said that he adjusted the valves, cleaned the carb again, and checked the compression. He also said that when he kept it in the shop overnight where it was warm, it would fire up pretty quickly, but when it's kept in the cold (where I keep it), it takes forever to start. His response is that it's just a really "cold-natured" bike. I'm not willing to believe that because I never had this trouble last winter, used to start in 3 or 4 kicks, no matter how cold it was. Also, when I do FINALLY get it started now, it seems to not have the power that it did before. It runs alot smoother now than it did before when I'm on the throttle, but it seems to back fire alot on deceleration. Any suggestions before I think about taking to another shop? Thanks everybody.