High Pitched Screetch...Uh Oh



I just ticked over the 200 mile mark on my chinese 80cc this week when I noticed a really ugly screetchy-scratchy noise coming from the engine.
My friend and I did some dirt biking through really dusty trails, and my first impression was that some dust or debris got into the piston cylinder.:eek:
I tightened every nut and bolt up, but the sound remains. It seems to be getting worse too. It really sounds like nails on a chalkboard, and as my rpms increases, the tempo of the noise does too which makes me suspect my theory is correct:eek:Does anyone know what this could be?

Take the clutch cover off and see if the adjuster knob is scraping the inside of the cover.