[boekel]

Yes, that's a CVT of the most common type, with variable-diameter pulleys and a belt. Strangely to me, the rear pulley diameter is the one which is controlled, unlike a typical snowmobile CVT.

it's the front, the rear is just spring loaded.
what's different to the systems I know (mopeds), is that the clutch is at the rear and not at the front.

And yes, good one to replace with fixed toothed belt pulleys.