IIRC you have to pull the idler assembly and go back to the stock belt size. Mark Rowe (Worldtour) has done it several times so he'd be best to consult on exactly what has to be done.
Rick
Owner of 00 #1611 Silver (Totalled) 98.5 T-Red SVT #6180
Buckshot77@msn.com
Misc 3L parts for sale