Motorcycle Repair: Temperature gauge, honda cbr600, temperature gauge

Question
I have a Honda CBR600 F-L(1990). When the bike is stationary or at slow speeds the temperarure gauge works fine,it gives a steady reading and it does increase as the engine gets warmer.However once i get any speed (50mph or above)the needle goes rapidly eratic and cant be read properly...i am new to biking please help if you can...

Answer
Hi Andy.
 The answer is simple.  You have a short in the wiring to that guage.

Get out the repair manual and trace down the wire, both visually and with a multimeter.  You will find the wire shorted out or arcing against another wire or ground.

Good luck.
FALCON