Hi guys, I just bought a 2008 crf450r. It had been sitting for a while wouldn't idle with the choke off and it sounded like when I gave it throttle the the rpms would stay high for a minute then come back down. I decided to clean the carb and check the jetting. I left all the Jets the same except I seated the pilot screw then backed it out 1 5/8 turns. Started it up and now it's popping and backfiring, after about 8 minutes of idling it puked up antifreeze. My buddy thinks it is lean. Any advice?