Usually this problem is low voltage after starting.
Charge battery and try again.
There was some kind of software update on some models.
Should be able to find it with the search function.
This should be the first thing to check.
I spent a couple hours tracing wires for nothing on mine...
When did it stop working? Was it right after the battery Change? If it was not working prior to the battery change then I would pull the speedo and check the wires on the back. Mine came off twice so far.
Speedometer sensor or something is not plugged in. You have a connection on the speedometer sensor wire, perhaps one under the tank and then in the speedometer housing itself..
Neil