Complex sentence: In those years the ZX-12R at at low speed to at high speed with ram-air intake, was the most powerful production motorcycle up to 2006 and the release of the ZX-14.
Split into simpler sentences: In those years the ZX-12R at at low speed to at high speed with ram-air intake. Was the most powerful production motorcycle up to 2006 and the release of the ZX-14.