..to get to the variator boss, you must remove the cvt cover, remove the nut that secures the variator to the crankshaft, and then slide back the washer, fan and flywheel...the boss is the tubular bushing that goes aroundthe shaft, through the next pulley of the variator...if you will search the 50cc boards, there are several pics and links to guide you through this process...
..my profile pic is of the inside of a cvt...the variator is to the left..
..how many miles does your scoot have on it?