check your axle sizes first but it should fit OK with some spacers on the sides and if the axle sizes differ it would just be a matter of getting bearings with different ID's or making a sleeve
a quick google search will give you wheel bearing sizes for the RS125 aprilia.
I beleive the RS125 axle may be the same as the CR85.
this is quoted from another site, bearing sizes, should be correct but do confirm before spending any money.
front 20mm id, 42mm od. rear 20mm id, 47mm od
hope that helps.
and Im currently putting similar wheels from a cagiva mito into my CRM250 (UK, Japan, Aus Urban-Enduro version of CR), should fit
PS: not wanting to dumb it down to much as your quiet posibly a bright person, the ID measurements need to match your axle size
then you just need to alight the wheel and chain with spacers, sort out front brakes (better off using the RS125 disc and then making an apater for your caliper)
its not a 2 second job, but once done properly will be worth it.