I don’t know what the Vapor is like but the Voyager has 3 settings: Tach, Tach/2 and Tach*2. With the bike at idle and the unit set on tach, the rpm reads 8000. With the unit set on tach/2 it reads around 4000. I’ve wired directly to the coil and wrapped around the plug wire with the same results. A couple guys I know tell me their Vapors have never been reliable as far as the tach. goes. Anyone else with the same problem? Thanks.