Generator style crankcases are designed with a stock-like original appearance and updated design features that improve overall engine strength and reliability Pre-clearanced for strokes up to and including 5" Motor mounts on crankcases for Knucklehead engines are machined to fit stock 1936-47 frames An adapter plate is included for 1948 and later style frames Designed for late style generator (two brush type) with 5/16" mounting bolts to eliminate early generator cradle/mounting strap bosses for simplicity and economics Use more readily available 1/4"-20 thread fasteners to mount gear cover, oil pump, tappet guides, timer, and timer advance bracket, except KN replacement Timken sprocket shaft main bearing, instead of stock straight roller bearings, which results in better flywheel assembly stability, placement, and longer engine life