Eh, why worry about the belt on bike?
I can't speark for other brands, but the drive belt on the Vision - an 850 lb machine with about 100 TQ at the rear wheel - has a maintenace replacement interval at 30,000 miles.
I had mine changed around 30,000 with a rear tire change so it wasn't a big deal. It was barely worn and the mechanic told me it would have probably lasted to 50,000 miles or more.
