2006 Mxz 550F Voltage issues

[Chadw90]

I have a 2006 mxz 550f in my garage that gauge works at idle, cuts out when revved up/riding.
Voltage regulator changed by owner and still having same issues. I haven’t been into these 550’s at all before.
Any ideas before i go ripping this unit apart?
Thanks

 

[Chadw90]

Pulled apart every connector on the machine, cleaned and re assembled. Battery voltage is 12.8v at idle, 14.6v when at about 4000rpm when the gauge cuts out.
Bad gauge?