This JIMS tappet pump and test tool allows you to test hydraulic tappets before assembling the valve train. By using pressurized oil, this unique tool allows you to fill the tappet with oil, while "feeling" the fitment of the hydraulic unit. You can easily diagnose loose or "spongy" tappets that could eventually lead to bleed down issues, or "sticky" tappets that won't pump up due to poor hydraulic unit fitment. Whether you simply change cams every once in a while, or your are an experienced engine builder, this tool will allow you to complete the final assembly of your cam chest and valve train with confidence knowing your tappets are pumped up, pass test and ready for action. Works with tappets for 1999 thru 2017 Twin Cams and 2017 to present Milwaukee Eight. A sleeve adapter to use the Jims test stand with 1984 thru 1999 Evolution Big Twin and 1986 thru 1990 Evolution Sportster tappets is available separately.