What symptoms were you experiencing that led you to use talcum powder on your belt? What were the results?
Clutch would snatch and drag on idle. The belt would grab and vibrate whilst engaging and make a horrific noise. If you open the little inspection hatch by the clutch and look at the belt whilst the clutch is disengaged and the engine is idling, the belt should just hang there quite still. Maybe dancing at little at the bottom loop that covers loosely over the engine crankshaft drive pulley.
Adding french chalk effectively adds lubrication to the belt and the whole clutch becomes much more behaved. You will still get a screeching noise whilst engaging though. I have over 1600 hours on the 280C.
