malossi variator not working on standard crank 125 ?

are the mallosi multivar's not designed to work on standard cranks? coz when i put it on the back plate of the vario with the runners on, sits on the part of the crank where there's no threads. ive got the thiuck washer at the back.

cheers

 

have the splines been stripped off by a previous varo letting go? sounds like a damaged crank to me. or the wrong m/var