YOST ADJUSTABLE IDLE/AIR SCREW CVYost has been making great performance parts for all Harley Davidson model stock and aftermarket carburetors for years! Stock CV carburetors have a small plug on the bottom backside of the carburetor that caps off access to the idle air mixture screw. When doing any upgrades, tuning, or performance work, having access to that is imperative. This kit includes a screw to help remove the plug along with a new spring, washer, O ring, and most importantly