if it follows the traditional nomenclature i would see that the f41 would be a 2001 cbr f4i
when i went to regester my bike to the insurance and on the bike title paperwork it was listed as a cbr f45 as a 2005 F4i
the 5 at the end i would just assume would be the model year of the bike

 

Its interesting that, because when I lift the seat of my 2002 F4i, on the bike is a sticker with model number and colour number etc...
For model number, its says CBR 600 F41, which is what puzzled me also........