I don't have the slightest idea about this but was told by a 30 year motorcycle mechanic that dry plates cause the coffee grinder noice. He is the one that told me to work the clutch during warmup to elimenate this, hence getting the wet clutch plates wet. Has worked everytime for me when the engine is cold(40 degree and less). Castrol 10w40 stopped this at all temps above 40 degree. Seems to me the holes are to let the oil into the basket while the engine is off. The oil drains back to the bottom of the engine when not running, raising the oil level, putting the basket deeper into the oil. Pull the level to disengage the clutch while the engine is not running and it would let oil into the plates and basket, hence oiling the wet clutch plates. If they were intended to be dry it wouldn't be a wet clutch.
My question is: Does drilling the basket at random (free hand) not put the spinning drum out of balance? Drilling consistantly helps but the slightest difference would cause an unbalance, correct?
Last edited by Chuck A.; 11-11-2012 at 12:36 PM.