The 250R engine would be too much for the 230F suspension to cope with. The 230F frame and plastics were never designed with radiators in mind either.
It is not something I would recommend.
So go either 250 or 230 as complete bikes.
C30F Power Up needle
2 turns out
Baffle out, Screens In
It starts,it runs,it gets to where all CRFs can get to without the valve or valve plate dramas