Abstract: An adjustable camshaft sprocket assembly for attachment to a camshaft. A camshaft sprocket is removably securable to a camshaft sprocket hub and moveable, independent of the camshaft sprocket hub when the camshaft sprocket assembly is mounted on the camshaft. An adjustment tool is used to adjust the camshaft sprocket comprising at least two extensions. The first extension is of a size to fit within one a corresponding opening in the camshaft hub. The second extension is of a size to pass though a different corresponding opening in the camshaft hub and fit within a corresponding opening in the camshaft sprocket. A handle extension is used for turning the adjustment tool about the second extension, which serves as a pivot.