Two things to try.
1) If it's a dry day then go ride it. A build up of moisture can cause problems for the gauges. You can put a fan on it, or go ride it. After a mile or so it should all reset. If they aren't working after 5 miles or so then go to step 2.
2) Turn ignition off, disconnect negative battery terminal, turn ignition on, touch negative cable to negative battery terminal. The gauges should reset to normal. Turn the ignition off and reconnect the battery.