yee haw
Best I know is you need a special wire to adapt the new tach into the streetbob's ECM, it then transfers all codes mileage and vin to the new tach and it takes 5 minutes, but that only applies to a new tach from HD and the wire would then be in the box along with the instructions. Sorry I can't be of any more help but you haven't exactly given alot of information.
And according to this thread you can only buy a new tach/speedo and once it's married to a vin that's it , it can't be sold and transfereed to someone else's bike. https://www.hdforums.com/forum/touri...on-gauges.html.
I found this using the search box at the top of the page there are about 3 pages of posts on this topic that came right up!



