Küryakyn offers a select number of complete Hypercharger kits assembled with a Blood Groove style trap door. The Blood Groove Trap Doors offer a styling alternative to standard trap doors; you get the same impressive performance no matter which style you choose.‘91-’06 Sportster Models with Stock Carb, Includes Küryakyn Crankcase Breather.9989, Black Body with Black Blood Groove Trap Door (lettered) & Black Butterflies.