I recently put a f4i guage cluster on my 919 . I have got everything to work except the tachometer. I checked the fuses and connections. The service manual says the ecm needs replacing. I dont know how could be since the bike runs fine. Doesnt that control everything.
you can check the voltage output on the tach signal wire it should be 10.5v minimum anything less and that circuit from the ecu is bad. If you did not short the tach signal wire the ecu should still be good.