36-52 Flathead, 36-47 Knucklehead, 48-54 Panhead
Note: For Kick Start Models only.
For precision belt adjustment, kits for aluminum-primary Big Twins include a BDL idler that makes sure belt tension is correct (tin primary models use tranny adjustment for correct belt tension). All kits use 31-tooth engine pulleys and 47-tooth clutch pulleys.