need help
 

hey guys
my name is devin and im 18 i just bought an FC but its hard for me to work on it because its over 200 miles away, im in lemoore, ca. im in the navy and cant leave base on the weekdays. my FC smokes alot when the rpms are winding down, it has a straight exhaust on it right now and my first thought was its just excess oil but im wanting more opinions on what it can be, its fine when the rpms are constant.