It's usually just the speed sensor that goes. You should check that before you buy a speedo.
2010 Cross Country
Stage 1 Map
V & H HO Slip ons
Big Bike Parts LED running lights
Show Chrome Mini LED fog lights
Victory Drivers Backrest
Victory Passenger Backrest with Luggage Rack
Ya gotta keep riding mate, mine stops when I stop too!
Likely the speed sensor things, my bro in laws Boardwalk speedo stopped not long after he took delivery if the bike, he's still waiting for a hip replacement so hasn't really ridden a brand new bike and the speedo not working.
Mines done 70,000 hard miles and working fine still.