Well I have seen written down that Honda has changed rings thickness several times.
Rings have tended to get thinner to maintain a seal as power has increased.
The 2006-2007 rings are 0.72mm
The 2008-2009 rings are 0.85mm
Are you using a factory or aftermarket piston.
If you are using and aftermarket that has been around a while they may have stayed with the thinner ring.
If you are using aftermarket piston then contact the maker.
They probably based their piston on a particular year and should be able to tell you what oem rings fit.
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