The standard 999, model year '03-04 was a 998 motor in every sense.Why?
The 999S 04 is a 998S/996R engine and the 05 model years were all "s" style engines with deep oil sump and S cams (base 999 and 999S). 999R was the same layout as well, just a different head and lighter crank.
I´m talking about Euro bikes, just to clarify. Don´t know what fancy shit they pulled off stateside.
Correct me if I am wrong