Motorcycle Repair: Revving problem, yamaha 550, out of the blue

Question
Good morning Chris.
Wonder if you can give me some clues as to what could be wrong with my motorcycle.  I have an '86 Yamaha 550 Seca and while idle, the engine turns at 3000 RPM (once the engine is warm).  I've made an appointment with a mechanic but he could only take me next week.  I was curious to know what can case this.
Help please.
Frank.

Answer
Hi Frank.
 Your idle should be a hair less than half that (approx 1400rpm).  Lower the idle with the idle screw.

 If this happened out of the blue, then you may want to look at the possibility that someone may have tampered with the bike.

Start with that and see what happens.
Good luck.
FALCON