Problem isn't weights or the clutch itself. That tapered end of the crank, is a completely separate part of the rest of the crank (it fits on splined end of cranks "main body"), and will develope excessive slack between the pto ends internal splines, and the main cranks external splines.
Sounds like an electric Impact wrench going at about 1/2 speed while impacting. (Like a V-8 engine with 2-3 rods ready to ventilate its oil pan at any second)
With engine shut off, make a mark on engines case (and on clutches sheave) that align, next, rotate the clutch forwards and backwards (without trying to humanly "start unit up")
Note the amount of movement of the clutches inner sheave, that is slack making all your noise.
Sh/tty design by Yamaha engineering. Even worse decision by Cat to even think of using this design, knowing customers are going to be very upset with it when it finally surfaces. Usually takes minimum of 800-1500 miles to begin rearing its ugly head.
Go look up engine on a site with micro-fiche, see crankshaft diagram. You'll see pto stub separate with a retaining plate and two (2) main bearings to support it. Again, p/ss poor engineering.