Technical Multipla over revving !

[dizzytracy]

Hello, I own a 2002 Multpila 1.6 petrol. Every now and then it revs quite high and the only way to stop it is to turn the engine off.
It can rev up to 4000rpm which scares the hell out of me . Mostly it will rev to 2000rpm.
Any ideas ?

 

[BikeDoc]

I take it you mean it's doing this without any throttle input from you?
Does it also take a while for the revs to drop away when you lift off the pedal sometimes?
Is the pedal travel 'normal' feeling-wise, i.e. any tight spots?
Could be an air-leak into the inlet somewhere, which is tricky to find, but you could try spraying 'Easy-Start' onto anywhwhere air could leak in (joints, pipes etc) while it's idling.
Any getting sucked in will change the engine sound momentarily.