More like a racing dry clutch. It's a way of lightening up the bike. No oil, lighter cover. more HP when chasing oz./grams. Power to weight and all that. Air cooled instead. Idle noise is very normal. Heat expands some, gives more room for the plates to bang at the big clutch outer, and w/lever pulled, the plates rattle a little farther away heat wise... so you add X is one way, Y the other and it makes ~ Music only a gear head would call that noise a pleasant note. It happens so fast, is the tap-tap; after the power ends, the whole pack floats off the big basket, then the power of the other cylinder causes it to tick. Oil quiets that down some. At speed you don't hear it because you load that pack on the one clutch outer side of those forks, or machined cutouts... depends on basket designs.