This is my first attempt at posting anything here so please be gentle! just finished a28ci flatty race build. everything went smooth during the build and the first startup was good also. Breakin went as planned as well. Shortly after break in motor started having sputtering and stumbling issues. Now won't idle but will run if throttle is cracked open slightly. Have cleaned carb, checked clearance and found exhaust to be at about .017 . Could thus be causing all my trouble?