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. 9984 Chrome Body with Chrome Blood Groove Trap Door & Chrome Butterflies,‘95-’98 Evo Big Twin with EFI*, Includes Küryakyn Crankcase Breather.