naw my stock 2000 gpr 50 with its stock bore does like 65-70ish. Although it has a 17.5mm carb, and i think that might be aftermarket cause i believe ti came wtih a 12mm.
Derbi GPR's are super awesome. Best 50cc in my opionion, although Aprilia RS50's are hot. If they carry the gpr let me, perhaps they can order parts for me. -jimmy