I need to replace the crankshaft in my 2008 scooter but see that there are 2 alternatives listed for this model referred to as Category 1 and 2. My investigations so far have revealed that the crank is matched to the bearings and the crankcase. There is a number marked on the crankshaft "521975" but I still don't know whether I need to order a category 1 or 2 replacement. Any ideas?
OEM Piaggio: 8423835001 - cat1
OEM Piaggio: 8423835002 - cat2